path: root/less.man

LESS(1)                     General Commands Manual                    LESS(1)



NAME
       less - opposite of more

SYNOPSIS
       less -?
       less --help
       less -V
       less --version
       less [-[+]aABcCdeEfFgGiIJKLmMnNqQrRsSuUVwWX~]
            [-b space] [-h lines] [-j line] [-k keyfile]
            [-{oO} logfile] [-p pattern] [-P prompt] [-t tag]
            [-T tagsfile] [-x tab,...] [-y lines] [-[z] lines]
            [-# shift] [+[+]cmd] [--] [filename]...
       (See  the  OPTIONS section for alternate option syntax with long option
       names.)

DESCRIPTION
       Less is a program similar to more(1), but which allows  backward  move‐
       ment in the file as well as forward movement.  Also, less does not have
       to read the entire input file before  starting,  so  with  large  input
       files  it  starts  up  faster  than text editors like vi(1).  Less uses
       termcap (or terminfo on some systems), so it can run on  a  variety  of
       terminals.   There is even limited support for hardcopy terminals.  (On
       a hardcopy terminal, lines which should be printed at the  top  of  the
       screen are prefixed with a caret.)

       Commands  are based on both more and vi.  Commands may be preceded by a
       decimal number, called N in the descriptions below.  The number is used
       by some commands, as indicated.

COMMANDS
       In  the following descriptions, ^X means control-X.  ESC stands for the
       ESCAPE key; for example ESC-v means the  two  character  sequence  "ES‐
       CAPE", then "v".

       h or H Help:  display  a  summary of these commands.  If you forget all
              the other commands, remember this one.

       SPACE or ^V or f or ^F
              Scroll forward N lines, default one window (see  option  -z  be‐
              low).  If N is more than the screen size, only the final screen‐
              ful is displayed.  Warning: some systems use  ^V  as  a  special
              literalization character.

       z      Like  SPACE,  but  if  N is specified, it becomes the new window
              size.

       ESC-SPACE
              Like SPACE, but scrolls a full screenful,  even  if  it  reaches
              end-of-file in the process.

       ENTER or RETURN or ^N or e or ^E or j or ^J
              Scroll  forward N lines, default 1.  The entire N lines are dis‐
              played, even if N is more than the screen size.

       d or ^D
              Scroll forward N lines, default one half of the screen size.  If
              N  is specified, it becomes the new default for subsequent d and
              u commands.

       b or ^B or ESC-v
              Scroll backward N lines, default one window (see option  -z  be‐
              low).  If N is more than the screen size, only the final screen‐
              ful is displayed.

       w      Like ESC-v, but if N is specified, it  becomes  the  new  window
              size.

       y or ^Y or ^P or k or ^K
              Scroll backward N lines, default 1.  The entire N lines are dis‐
              played, even if N is more than the screen size.   Warning:  some
              systems use ^Y as a special job control character.

       u or ^U
              Scroll  backward  N  lines, default one half of the screen size.
              If N is specified, it becomes the new default for  subsequent  d
              and u commands.

       J      Like j, but continues to scroll beyond the end of the file.

       K or Y Like  k,  but  continues  to  scroll beyond the beginning of the
              file.

       ESC-) or RIGHTARROW
              Scroll horizontally right N characters, default half the  screen
              width  (see  the -# option).  If a number N is specified, it be‐
              comes the default for future RIGHTARROW and LEFTARROW  commands.
              While  the  text  is  scrolled,  it acts as though the -S option
              (chop lines) were in effect.

       ESC-( or LEFTARROW
              Scroll horizontally left N characters, default half  the  screen
              width  (see  the -# option).  If a number N is specified, it be‐
              comes the default for future RIGHTARROW and LEFTARROW commands.

       ESC-} or ^RIGHTARROW
              Scroll horizontally right to show the end of  the  longest  dis‐
              played line.

       ESC-{ or ^LEFTARROW
              Scroll horizontally left back to the first column.

       r or ^R or ^L
              Repaint the screen.

       R      Repaint  the  screen,  discarding  any buffered input.  That is,
              reload the current file.  Useful if the file is  changing  while
              it is being viewed.

       F      Scroll  forward, and keep trying to read when the end of file is
              reached.  Normally this command would be used  when  already  at
              the  end of the file.  It is a way to monitor the tail of a file
              which is growing while it is being  viewed.   (The  behavior  is
              similar  to  the  "tail  -f" command.)  To stop waiting for more
              data, enter the interrupt character (usually  ^C).   On  systems
              which support poll(2) you can also use ^X or the character spec‐
              ified by the --intr option.  If the input  is  a  pipe  and  the
              --exit-follow-on-close  option is in effect, less will automati‐
              cally stop waiting for data when the input side of the  pipe  is
              closed.

       ESC-F  Like  F,  but  as soon as a line is found which matches the last
              search pattern, the terminal bell is rung and forward  scrolling
              stops.

       g or < or ESC-<
              Go to line N in the file, default 1 (beginning of file).  (Warn‐
              ing: this may be slow if N is large.)

       G or > or ESC->
              Go to line N in the file, default the end of the  file.   (Warn‐
              ing:  this  may  be slow if N is large, or if N is not specified
              and standard input, rather than a file, is being read.)

       ESC-G  Same as G, except if no number N is specified and the  input  is
              standard  input,  goes  to  the  last  line  which  is currently
              buffered.

       p or % Go to a position N percent into the file.  N should be between 0
              and 100, and may contain a decimal point.

       P      Go to the line containing byte offset N in the file.

       {      If a left curly bracket appears in the top line displayed on the
              screen, the { command  will  go  to  the  matching  right  curly
              bracket.   The matching right curly bracket is positioned on the
              bottom line of the screen.  If there is more than one left curly
              bracket  on  the top line, a number N may be used to specify the
              N-th bracket on the line.

       }      If a right curly bracket appears in the bottom line displayed on
              the  screen,  the  }  command will go to the matching left curly
              bracket.  The matching left curly bracket is positioned  on  the
              top  line  of the screen.  If there is more than one right curly
              bracket on the bottom line, a number N may be  used  to  specify
              the N-th bracket on the line.

       (      Like {, but applies to parentheses rather than curly brackets.

       )      Like }, but applies to parentheses rather than curly brackets.

       [      Like  {, but applies to square brackets rather than curly brack‐
              ets.

       ]      Like }, but applies to square brackets rather than curly  brack‐
              ets.

       ESC-^F Followed  by two characters, acts like {, but uses the two char‐
              acters as open and close brackets, respectively.   For  example,
              "ESC  ^F < >" could be used to go forward to the > which matches
              the < in the top displayed line.

       ESC-^B Followed by two characters, acts like }, but uses the two  char‐
              acters  as  open and close brackets, respectively.  For example,
              "ESC ^B < >" could be used to go backward to the < which matches
              the > in the bottom displayed line.

       m      Followed  by  any lowercase or uppercase letter, marks the first
              displayed line with that letter.  If the status  column  is  en‐
              abled  via  the  -J  option,  the status column shows the marked
              line.

       M      Acts like m, except the last displayed  line  is  marked  rather
              than the first displayed line.

       '      (Single  quote.)  Followed by any lowercase or uppercase letter,
              returns to the position which was previously  marked  with  that
              letter.   Followed by another single quote, returns to the posi‐
              tion at which the last "large" movement  command  was  executed.
              Followed  by a ^ or $, jumps to the beginning or end of the file
              respectively.  Marks are preserved when a new file is  examined,
              so the ' command can be used to switch between input files.

       ^X^X   Same as single quote.

       ESC-m  Followed  by  any lowercase or uppercase letter, clears the mark
              identified by that letter.

       /pattern
              Search forward in the file for the N-th line containing the pat‐
              tern.  N defaults to 1.  The pattern is a regular expression, as
              recognized by the regular expression library  supplied  by  your
              system.   By default, searching is case-sensitive (uppercase and
              lowercase are considered different); the -i option can  be  used
              to  change  this.  The search starts at the first line displayed
              (but see the -a and -j options, which change this).

              Certain characters are special if entered at  the  beginning  of
              the  pattern;  they modify the type of search rather than become
              part of the pattern:

              ^N or !
                     Search for lines which do NOT match the pattern.

              ^E or *
                     Search multiple files.  That is, if  the  search  reaches
                     the  END of the current file without finding a match, the
                     search continues in the next file  in  the  command  line
                     list.

              ^F or @
                     Begin  the  search at the first line of the FIRST file in
                     the command line list, regardless of  what  is  currently
                     displayed  on  the screen or the settings of the -a or -j
                     options.

              ^K     Highlight any text which matches the pattern on the  cur‐
                     rent screen, but don't move to the first match (KEEP cur‐
                     rent position).

              ^R     Don't interpret regular expression  metacharacters;  that
                     is, do a simple textual comparison.

              ^S     Followed  by  a digit N between 1 and 5.  Only text which
                     has a non-empty match for the N-th parenthesized SUB-PAT‐
                     TERN will be considered to match the pattern.  (Supported
                     only if less is built with one of the regular  expression
                     libraries  posix, pcre, or pcre2.)  Multiple ^S modifiers
                     can be specified, to match more than one sub-pattern.

              ^W     WRAP around the current file.  That  is,  if  the  search
                     reaches  the  end  of  the current file without finding a
                     match, the search continues from the first  line  of  the
                     current  file up to the line where it started.  If the ^W
                     modifier is set, the ^E modifier is ignored.

       ?pattern
              Search backward in the file for the  N-th  line  containing  the
              pattern.   The search starts at the last line displayed (but see
              the -a and -j options, which change this).

              Certain characters are special as in the / command:

              ^N or !
                     Search for lines which do NOT match the pattern.

              ^E or *
                     Search multiple files.  That is, if  the  search  reaches
                     the  beginning  of  the  current  file  without finding a
                     match, the search continues in the previous file  in  the
                     command line list.

              ^F or @
                     Begin the search at the last line of the last file in the
                     command line list, regardless of what is  currently  dis‐
                     played  on the screen or the settings of the -a or -j op‐
                     tions.

              ^K     As in forward searches.

              ^R     As in forward searches.

              ^S     As in forward searches.

              ^W     WRAP around the current file.  That  is,  if  the  search
                     reaches the beginning of the current file without finding
                     a match, the search continues from the last line  of  the
                     current file up to the line where it started.

       ESC-/pattern
              Same as "/*".

       ESC-?pattern
              Same as "?*".

       n      Repeat  previous  search, for N-th line containing the last pat‐
              tern.  If the previous search was modified by ^N, the search  is
              made  for the N-th line NOT containing the pattern.  If the pre‐
              vious search was modified by ^E, the  search  continues  in  the
              next  (or  previous)  file if not satisfied in the current file.
              If the previous search was modified by ^R, the  search  is  done
              without  using  regular  expressions.  There is no effect if the
              previous search was modified by ^F or ^K.

       N      Repeat previous search, but in the reverse direction.

       ESC-n  Repeat previous search, but crossing file boundaries.   The  ef‐
              fect is as if the previous search were modified by *.

       ESC-N  Repeat  previous search, but in the reverse direction and cross‐
              ing file boundaries.

       ESC-u  Undo search highlighting.   Turn  off  highlighting  of  strings
              matching the current search pattern.  If highlighting is already
              off because of a previous ESC-u command, turn highlighting  back
              on.   Any  search  command  will also turn highlighting back on.
              (Highlighting can also be disabled by toggling the -G option; in
              that case search commands do not turn highlighting back on.)

       ESC-U  Like  ESC-u  but  also  clears the saved search pattern.  If the
              status column is enabled via the  -J  option,  this  clears  all
              search matches marked in the status column.

       &pattern
              Display  only  lines which match the pattern; lines which do not
              match the pattern are not displayed.  If pattern  is  empty  (if
              you  type  &  immediately  followed  by ENTER), any filtering is
              turned off, and all lines are displayed.  While filtering is  in
              effect,  an  ampersand  is  displayed  at  the  beginning of the
              prompt, as a reminder that some lines in the file may be hidden.
              Multiple  &  commands  may  be entered, in which case only lines
              which match all of the patterns will be displayed.

              Certain characters are special as in the / command:

              ^N or !
                     Display only lines which do NOT match the pattern.

              ^R     Don't interpret regular expression  metacharacters;  that
                     is, do a simple textual comparison.

       :e [filename]
              Examine  a  new file.  If the filename is missing, the "current"
              file (see the :n and :p commands below) from the list  of  files
              in  the  command line is re-examined.  A percent sign (%) in the
              filename is replaced by the name of the current file.   A  pound
              sign  (#)  is  replaced  by  the name of the previously examined
              file.  However, two consecutive percent  signs  are  simply  re‐
              placed  with  a single percent sign.  This allows you to enter a
              filename that contains a percent sign in the  name.   Similarly,
              two  consecutive  pound  signs  are replaced with a single pound
              sign.  The filename is inserted into the command  line  list  of
              files  so  that it can be seen by subsequent :n and :p commands.
              If the filename consists of several files, they are all inserted
              into  the  list  of files and the first one is examined.  If the
              filename contains one or more spaces, the entire filename should
              be enclosed in double quotes (also see the -" option).

       ^X^V or E
              Same  as :e.  Warning: some systems use ^V as a special literal‐
              ization character.  On such systems, you may not be able to  use
              ^V.

       :n     Examine  the next file (from the list of files given in the com‐
              mand line).  If a number N is specified, the N-th next  file  is
              examined.

       :p     Examine the previous file in the command line list.  If a number
              N is specified, the N-th previous file is examined.

       :x     Examine the first file in the command line list.  If a number  N
              is specified, the N-th file in the list is examined.

       :d     Remove the current file from the list of files.

       t      Go  to the next tag, if there were more than one matches for the
              current tag.  See the -t option for more details about tags.

       T      Go to the previous tag, if there were more than one matches  for
              the current tag.

       = or ^G or :f
              Prints  some  information about the file being viewed, including
              its name and the line number and byte offset of the bottom  line
              being  displayed.  If possible, it also prints the length of the
              file, the number of lines in the file and  the  percent  of  the
              file above the last displayed line.

       -      Followed  by one of the command line option letters (see OPTIONS
              below), this will change the setting of that option and print  a
              message  describing the new setting.  If a ^P (CONTROL-P) is en‐
              tered immediately after the dash, the setting of the  option  is
              changed  but  no message is printed.  If the option letter has a
              numeric value (such as -b or -h), or a string value (such as  -P
              or  -t), a new value may be entered after the option letter.  If
              no new value is entered, a message describing the  current  set‐
              ting is printed and nothing is changed.

       --     Like  the  -  command, but takes a long option name (see OPTIONS
              below) rather than a single option letter.  You must press ENTER
              or  RETURN after typing the option name.  A ^P immediately after
              the second dash suppresses printing of a message describing  the
              new setting, as in the - command.

       -+     Followed by one of the command line option letters this will re‐
              set the option to its default setting and print  a  message  de‐
              scribing  the  new  setting.   (The  "-+X" command does the same
              thing as "-+X" on the command line.)  This  does  not  work  for
              string-valued options.

       --+    Like  the -+ command, but takes a long option name rather than a
              single option letter.

       -!     Followed by one of the command line option  letters,  this  will
              reset  the  option  to the "opposite" of its default setting and
              print a message describing the new setting.  This does not  work
              for numeric or string-valued options.

       --!    Like  the -! command, but takes a long option name rather than a
              single option letter.

       _      (Underscore.)  Followed by one of the command line  option  let‐
              ters,  this  will print a message describing the current setting
              of that option.  The setting of the option is not changed.

       __     (Double underscore.)  Like the _ (underscore) command, but takes
              a long option name rather than a single option letter.  You must
              press ENTER or RETURN after typing the option name.

       +cmd   Causes the specified cmd to be executed each time a new file  is
              examined.  For example, +G causes less to initially display each
              file starting at the end rather than the beginning.

       V      Prints the version number of less being run.

       q or Q or :q or :Q or ZZ
              Exits less.

       The following six commands may or may not be valid, depending  on  your
       particular installation.

       v      Invokes  an  editor  to edit the current file being viewed.  The
              editor is taken from the environment variable VISUAL if defined,
              or  EDITOR if VISUAL is not defined, or defaults to "vi" if nei‐
              ther VISUAL nor EDITOR is defined.  See also the  discussion  of
              LESSEDIT under the section on PROMPTS below.

       ! shell-command
              Invokes  a shell to run the shell-command given.  A percent sign
              (%) in the command is replaced by the name of the current  file.
              A pound sign (#) is replaced by the name of the previously exam‐
              ined file.  "!!" repeats the last shell command.   "!"  with  no
              shell  command  simply  invokes  a  shell.  On Unix systems, the
              shell is taken from the environment variable SHELL, or  defaults
              to  "sh".   On  MS-DOS and OS/2 systems, the shell is the normal
              command processor.

       # shell-command
              Similar to the "!" command, except that the command is  expanded
              in the same way as prompt strings.  For example, the name of the
              current file would be given as "%f".

       | <m> shell-command
              <m> represents any mark letter.  Pipes a section  of  the  input
              file  to the given shell command.  The section of the file to be
              piped is between the position marked by the letter and the  cur‐
              rent  screen.  The entire current screen is included, regardless
              of whether the marked position is before or  after  the  current
              screen.   <m> may also be ^ or $ to indicate beginning or end of
              file respectively.  If <m> is . or newline, the  current  screen
              is piped.

       s filename
              Save  the  input  to  a file.  This works only if the input is a
              pipe, not an ordinary file.

       ^X     When the "Waiting for data" message is displayed, such as  while
              in  the  F  command, pressing ^X will stop less from waiting and
              return to a prompt.  This may cause less to think that the  file
              ends  at the current position, so it may be necessary to use the
              R or F command to see more data.  The --intr option can be  used
              to  specify  a  different  character to use instead of ^X.  This
              command works only on systems that support the poll(2) function.
              On systems without poll(2), the interrupt character (usually ^C)
              can be used instead.

OPTIONS
       Command line options are described below.  Most options may be  changed
       while less is running, via the "-" command.

       Some  options  may be given in one of two forms: either a dash followed
       by a single letter, or two dashes followed by a long  option  name.   A
       long  option name may be abbreviated as long as the abbreviation is un‐
       ambiguous.  For example, --quit-at-eof may be abbreviated  --quit,  but
       not --qui, since both --quit-at-eof and --quiet begin with --qui.  Some
       long option names are in uppercase, such as --QUIT-AT-EOF, as  distinct
       from  --quit-at-eof.  Such option names need only have their first let‐
       ter capitalized; the remainder of the name may be in either case.   For
       example, --Quit-at-eof is equivalent to --QUIT-AT-EOF.

       Options are also taken from the environment variable "LESS".  For exam‐
       ple, to avoid typing "less -options ..." each time less is invoked, you
       might tell csh:

       setenv LESS "-options"

       or if you use sh:

       LESS="-options"; export LESS

       On  MS-DOS,  you don't need the quotes, but you should replace any per‐
       cent signs in the options string by double percent signs.

       The environment variable is parsed before the command line, so  command
       line  options override the LESS environment variable.  If an option ap‐
       pears in the LESS variable, it can be reset to its default value on the
       command line by beginning the command line option with "-+".

       Some  options  like -k or -D require a string to follow the option let‐
       ter.  The string for that option is considered to  end  when  a  dollar
       sign ($) is found.  For example, you can set two -D options like this:

       LESS="Dn9.1$Ds4.1"

       If  the  --use-backslash  option appears earlier in the options, then a
       dollar sign or backslash may be included literally in an option  string
       by preceding it with a backslash.  If the --use-backslash option is not
       in effect, then backslashes are not treated specially, and there is  no
       way to include a dollar sign in the option string.

       -? or --help
              This  option displays a summary of the commands accepted by less
              (the same as the h command).  (Depending on how your  shell  in‐
              terprets  the  question  mark,  it may be necessary to quote the
              question mark, thus: "-\?".)

       -a or --search-skip-screen
              By default, forward searches start at the top of  the  displayed
              screen  and  backwards  searches start at the bottom of the dis‐
              played screen (except for repeated searches invoked by the n  or
              N  commands,  which  start after or before the "target" line re‐
              spectively; see the -j option for more about the  target  line).
              The  -a  option  causes forward searches to instead start at the
              bottom of the screen and backward searches to start at  the  top
              of the screen, thus skipping all lines displayed on the screen.

       -A or --SEARCH-SKIP-SCREEN
              Causes  all forward searches (not just non-repeated searches) to
              start just after the target line, and all backward  searches  to
              start  just before the target line.  Thus, forward searches will
              skip part of the displayed screen (from the first line up to and
              including  the  target line).  Similarly backwards searches will
              skip the displayed screen from the last line up to and including
              the target line.  This was the default behavior in less versions
              prior to 441.

       -bn or --buffers=n
              Specifies the amount of buffer space  less  will  use  for  each
              file,  in  units of kilobytes (1024 bytes).  By default 64 KB of
              buffer space is used for each file (unless the file is  a  pipe;
              see  the  -B  option).   The  -b option specifies instead that n
              kilobytes of buffer space should be used for each file.  If n is
              -1,  buffer  space is unlimited; that is, the entire file can be
              read into memory.

       -B or --auto-buffers
              By default, when data is read from a pipe, buffers are allocated
              automatically as needed.  If a large amount of data is read from
              the pipe, this can cause a large amount of memory  to  be  allo‐
              cated.  The -B option disables this automatic allocation of buf‐
              fers for pipes, so that only 64 KB (or the amount of space spec‐
              ified  by  the -b option) is used for the pipe.  Warning: use of
              -B can result in erroneous display, since only the most recently
              viewed  part  of  the  piped data is kept in memory; any earlier
              data is lost.  Lost characters are displayed as question marks.

       -c or --clear-screen
              Causes full screen repaints to be  painted  from  the  top  line
              down.   By  default,  full screen repaints are done by scrolling
              from the bottom of the screen.

       -C or --CLEAR-SCREEN
              Same as -c, for compatibility with older versions of less.

       -d or --dumb
              The -d option suppresses the error message normally displayed if
              the  terminal is dumb; that is, lacks some important capability,
              such as the ability to clear the screen or scroll backward.  The
              -d  option  does  not otherwise change the behavior of less on a
              dumb terminal.

       -Dxcolor or --color=xcolor
              Changes the color of different parts of the displayed  text.   x
              is a single character which selects the type of text whose color
              is being set:

              B      Binary characters.

              C      Control characters.

              E      Errors and informational messages.

              H      Header lines and columns, set via the --header option.

              M      Mark letters in the status column.

              N      Line numbers enabled via the -N option.

              P      Prompts.

              R      The rscroll character.

              S      Search results.

              1-5    The text in a  search  result  which  matches  the  first
                     through  fifth  parenthesized  sub-pattern.   Sub-pattern
                     coloring works only if less is built with one of the reg‐
                     ular expression libraries posix, pcre, or pcre2.

              W      The highlight enabled via the -w option.

              d      Bold text.

              k      Blinking text.

              s      Standout text.

              u      Underlined text.

              The  uppercase  letters  and  digits  can  be used only when the
              --use-color option is enabled.  When text color is specified  by
              both  an  uppercase letter and a lowercase letter, the uppercase
              letter takes precedence.  For example, error messages  are  nor‐
              mally  displayed  as  standout text.  So if both "s" and "E" are
              given a color, the "E" color applies to error messages, and  the
              "s"  color applies to other standout text.  The "d" and "u" let‐
              ters refer to bold and underline  text  formed  by  overstriking
              with  backspaces (see the -U option), not to text using ANSI es‐
              cape sequences with the -R option.

              A lowercase letter may be followed by a + to indicate  that  the
              normal  format  change  and  the  specified color should both be
              used.  For example, -Dug displays underlined text as green with‐
              out  underlining;  the green color has replaced the usual under‐
              line formatting.  But -Du+g displays  underlined  text  as  both
              green and in underlined format.

              color is either a 4-bit color string or an 8-bit color string:

              A  4-bit  color string is zero, one or two characters, where the
              first character specifies the foreground color  and  the  second
              specifies the background color as follows:

              b      Blue

              c      Cyan

              g      Green

              k      Black

              m      Magenta

              r      Red

              w      White

              y      Yellow

              The  corresponding  uppercase letter denotes a brighter shade of
              the color.  For example, -DNGk displays line numbers  as  bright
              green  text on a black background, and -DEbR displays error mes‐
              sages as blue text on a bright red background.  If either  char‐
              acter  is a "-" or is omitted, the corresponding color is set to
              that of normal text.

              An 8-bit color string is one or two decimal  integers  separated
              by a dot, where the first integer specifies the foreground color
              and the second specifies the background color.  Each integer  is
              a  value  between 0 and 255 inclusive which selects a "CSI 38;5"
              color value (see
              https://en.wikipedia.org/wiki/ANSI_escape_code#SGR)  If   either
              integer  is  a "-" or is omitted, the corresponding color is set
              to that of normal text.  On MS-DOS versions of less, 8-bit color
              is  not  supported;  instead,  decimal values are interpreted as
              4-bit CHAR_INFO.Attributes values (see
              https://docs.microsoft.com/en-us/windows/console/char-info-str).

              On MS-DOS only, the -Da option may be  used  to  specify  strict
              parsing  of  ANSI  color  (SGR)  sequences when the -R option is
              used.  Without this  option,  sequences  that  change  text  at‐
              tributes (bold, underline, etc.) may clear the text color.

       -e or --quit-at-eof
              Causes  less  to  automatically  exit the second time it reaches
              end-of-file.  By default, the only way to exit less is  via  the
              "q" command.

       -E or --QUIT-AT-EOF
              Causes less to automatically exit the first time it reaches end-
              of-file.

       -f or --force
              Forces non-regular files to be opened.  (A non-regular file is a
              directory  or a device special file.)  Also suppresses the warn‐
              ing message when a binary file is opened.  By default, less will
              refuse to open non-regular files.  Note that some operating sys‐
              tems will not allow directories to be read, even if -f is set.

       -F or --quit-if-one-screen
              Causes less to automatically exit if the entire file can be dis‐
              played on the first screen.

       -g or --hilite-search
              Normally,  less  will highlight ALL strings which match the last
              search command.  The -g option changes this  behavior  to  high‐
              light  only  the  particular  string which was found by the last
              search command.  This can cause less to run somewhat faster than
              the default.

       -G or --HILITE-SEARCH
              The  -G  option  suppresses all highlighting of strings found by
              search commands.

       -hn or --max-back-scroll=n
              Specifies a maximum number of lines to scroll backward.   If  it
              is necessary to scroll backward more than n lines, the screen is
              repainted in a forward direction instead.  (If the terminal does
              not have the ability to scroll backward, -h0 is implied.)

       -i or --ignore-case
              Causes searches to ignore case; that is, uppercase and lowercase
              are considered identical.  This option is ignored if any  upper‐
              case  letters appear in the search pattern; in other words, if a
              pattern contains uppercase letters, then that  search  does  not
              ignore case.

       -I or --IGNORE-CASE
              Like  -i,  but searches ignore case even if the pattern contains
              uppercase letters.

       -jn or --jump-target=n
              Specifies a line on the screen where the "target" line is to  be
              positioned.   The  target line is the line specified by any com‐
              mand to search for a pattern, jump to a line number, jump  to  a
              file percentage or jump to a tag.  The screen line may be speci‐
              fied by a number: the top line on the screen is 1, the  next  is
              2, and so on.  The number may be negative to specify a line rel‐
              ative to the bottom of the screen: the bottom line on the screen
              is  -1, the second to the bottom is -2, and so on.  Alternately,
              the screen line may be specified as a fraction of the height  of
              the  screen,  starting with a decimal point: .5 is in the middle
              of the screen, .3 is three tenths down from the first line,  and
              so  on.  If the line is specified as a fraction, the actual line
              number is recalculated if the terminal window  is  resized.   If
              any  form  of  the  -j option is used, repeated forward searches
              (invoked with "n" or "N") begin at the  line  immediately  after
              the  target  line,  and  repeated backward searches begin at the
              target line, unless changed by -a or -A.  For example, if  "-j4"
              is  used,  the  target line is the fourth line on the screen, so
              forward searches begin at the fifth line on the screen.  However
              nonrepeated  searches (invoked with "/" or "?")  always begin at
              the start or end of the current screen respectively.

       -J or --status-column
              Displays a status column at the left edge of  the  screen.   The
              character displayed in the status column may be one of:

              >      The line is chopped with the -S option, and the text that
                     is chopped off beyond the right edge of the  screen  con‐
                     tains a match for the current search.

              <      The  line  is  horizontally shifted, and the text that is
                     shifted beyond the left side of  the  screen  contains  a
                     match for the current search.

              =      The  line  is  both  chopped  and  shifted, and there are
                     matches beyond both sides of the screen.

              *      There are matches in the visible part  of  the  line  but
                     none to the right or left of it.

              a-z, A-Z
                     The  line  has  been marked with the corresponding letter
                     via the m command.

       -kfilename or --lesskey-file=filename
              Causes less to open and interpret the named file as a lesskey(1)
              binary  file.   Multiple  -k  options  may be specified.  If the
              LESSKEY or LESSKEY_SYSTEM environment variable is set, or  if  a
              lesskey file is found in a standard place (see KEY BINDINGS), it
              is also used as a lesskey file.

       --lesskey-src=filename
              Causes less to open and interpret the named file as a lesskey(1)
              source  file.   If the LESSKEYIN or LESSKEYIN_SYSTEM environment
              variable is set, or if a lesskey source file is found in a stan‐
              dard  place  (see  KEY  BINDINGS),  it is also used as a lesskey
              source file.  Prior to version 582, the lesskey  program  needed
              to  be  run to convert a lesskey source file to a lesskey binary
              file for less to use.  Newer versions of less read  the  lesskey
              source  file  directly  and ignore the binary file if the source
              file exists.

       -K or --quit-on-intr
              Causes less to exit immediately (with status 2) when  an  inter‐
              rupt  character  (usually  ^C) is typed.  Normally, an interrupt
              character causes less to stop whatever it is doing and return to
              its  command  prompt.  Note that use of this option makes it im‐
              possible to return to the command prompt from the "F" command.

       -L or --no-lessopen
              Ignore the LESSOPEN environment variable  (see  the  INPUT  PRE‐
              PROCESSOR  section  below).   This option can be set from within
              less, but it will apply only to files opened  subsequently,  not
              to the file which is currently open.

       -m or --long-prompt
              Causes less to prompt verbosely (like more(1)), with the percent
              into the file.  By default, less prompts with a colon.

       -M or --LONG-PROMPT
              Causes less to prompt even more verbosely than more(1).

       -n or --line-numbers
              Suppresses line numbers.  The default (to use line numbers)  may
              cause  less  to run more slowly in some cases, especially with a
              very large input file.  Suppressing line numbers with the -n op‐
              tion  will  avoid  this  problem.  Using line numbers means: the
              line number will be displayed in the verbose prompt and in the =
              command,  and the v command will pass the current line number to
              the editor (see also the discussion of LESSEDIT in  PROMPTS  be‐
              low).

       -N or --LINE-NUMBERS
              Causes  a  line  number to be displayed at the beginning of each
              line in the display.

       -ofilename or --log-file=filename
              Causes less to copy its input to the named file as it  is  being
              viewed.  This applies only when the input file is a pipe, not an
              ordinary file.  If the file already exists, less  will  ask  for
              confirmation before overwriting it.

       -Ofilename or --LOG-FILE=filename
              The -O option is like -o, but it will overwrite an existing file
              without asking for confirmation.

              If no log file has been specified, the -o and -O options can  be
              used  from  within  less  to specify a log file.  Without a file
              name, they will simply report the name of the log file.  The "s"
              command is equivalent to specifying -o from within less.

       -ppattern or --pattern=pattern
              The  -p  option  on the command line is equivalent to specifying
              +/pattern; that is, it tells less to start at the  first  occur‐
              rence of pattern in the file.

       -Pprompt or --prompt=prompt
              Provides  a  way  to  tailor the three prompt styles to your own
              preference.  This option would normally be put in the LESS envi‐
              ronment variable, rather than being typed in with each less com‐
              mand.  Such an option must either be the last option in the LESS
              variable, or be terminated by a dollar sign.
               -Ps  followed by a string changes the default (short) prompt to
              that string.
               -Pm changes the medium (-m) prompt.
               -PM changes the long (-M) prompt.
               -Ph changes the prompt for the help screen.
               -P= changes the message printed by the = command.
               -Pw changes the message printed while waiting for data (in  the
              "F" command).

              All  prompt strings consist of a sequence of letters and special
              escape sequences.  See the section on PROMPTS for more details.

       -q or --quiet or --silent
              Causes moderately "quiet" operation: the terminal  bell  is  not
              rung if an attempt is made to scroll past the end of the file or
              before the beginning of the file.  If the terminal has a "visual
              bell",  it  is  used  instead.  The bell will be rung on certain
              other errors, such as typing an invalid character.  The  default
              is to ring the terminal bell in all such cases.

       -Q or --QUIET or --SILENT
              Causes  totally  "quiet"  operation:  the terminal bell is never
              rung.  If the terminal has a "visual bell", it is  used  in  all
              cases where the terminal bell would have been rung.

       -r or --raw-control-chars
              Causes "raw" control characters to be displayed.  The default is
              to display control characters using the caret notation; for  ex‐
              ample,  a  control-A (octal 001) is displayed as "^A" (with some
              exceptions as described under the -U option).  Warning: when the
              -r  option is used, less cannot keep track of the actual appear‐
              ance of the screen (since this depends on  how  the  screen  re‐
              sponds  to  each type of control character).  Thus, various dis‐
              play problems may result, such as long lines being split in  the
              wrong place.

              USE OF THE -r OPTION IS NOT RECOMMENDED.

       -R or --RAW-CONTROL-CHARS
              Like -r, but only ANSI "color" escape sequences and OSC 8 hyper‐
              link sequences are output in "raw" form.  Unlike -r, the  screen
              appearance  is  maintained correctly, provided that there are no
              escape sequences in the file other than these  types  of  escape
              sequences.   Color  escape sequences are only supported when the
              color is changed within one line, not across  lines.   In  other
              words,  the beginning of each line is assumed to be normal (non-
              colored), regardless of any escape sequences in previous  lines.
              For the purpose of keeping track of screen appearance, these es‐
              cape sequences are assumed to not move the cursor.

              OSC 8 hyperlinks are sequences of the form:

                   ESC ] 8 ; ... \7

              The terminating sequence may be either a BEL character  (\7)  or
              the two-character sequence "ESC \".

              ANSI color escape sequences are sequences of the form:

                   ESC [ ... m

              where  the "..." is zero or more color specification characters.
              You can make less think that characters other than "m"  can  end
              ANSI  color escape sequences by setting the environment variable
              LESSANSIENDCHARS to the list of characters which can end a color
              escape  sequence.   And  you can make less think that characters
              other than the standard ones may appear between the ESC and  the
              m  by  setting  the environment variable LESSANSIMIDCHARS to the
              list of characters which can appear.

       -s or --squeeze-blank-lines
              Causes consecutive blank lines to  be  squeezed  into  a  single
              blank line.  This is useful when viewing nroff output.

       -S or --chop-long-lines
              Causes  lines  longer than the screen width to be chopped (trun‐
              cated) rather than wrapped.  That is, the portion of a long line
              that does not fit in the screen width is not displayed until you
              press RIGHT-ARROW.  The default is to wrap long lines; that  is,
              display the remainder on the next line.  See also the --wordwrap
              option.

       -ttag or --tag=tag
              The -t option, followed immediately by a TAG, will edit the file
              containing  that tag.  For this to work, tag information must be
              available; for example, there may be a file in the  current  di‐
              rectory called "tags", which was previously built by ctags(1) or
              an equivalent command.  If the environment variable LESSGLOBALT‐
              AGS  is  set, it is taken to be the name of a command compatible
              with global(1), and that command is executed to  find  the  tag.
              (See  http://www.gnu.org/software/global/global.html).   The  -t
              option may also be specified from within less (using the -  com‐
              mand)  as  a  way  of examining a new file.  The command ":t" is
              equivalent to specifying -t from within less.

       -Ttagsfile or --tag-file=tagsfile
              Specifies a tags file to be used instead of "tags".

       -u or --underline-special
              Causes backspaces and carriage returns to be treated  as  print‐
              able  characters;  that  is,  they are sent to the terminal when
              they appear in the input.

       -U or --UNDERLINE-SPECIAL
              Causes backspaces, tabs, carriage returns and "formatting  char‐
              acters" (as defined by Unicode) to be treated as control charac‐
              ters; that is, they are handled as specified by the -r option.

              By default, if neither -u nor -U is given, backspaces which  ap‐
              pear  adjacent to an underscore character are treated specially:
              the underlined text is displayed using the  terminal's  hardware
              underlining  capability.   Also, backspaces which appear between
              two identical characters are treated specially:  the  overstruck
              text is printed using the terminal's hardware boldface capabili‐
              ty.  Other backspaces are  deleted,  along  with  the  preceding
              character.   Carriage  returns immediately followed by a newline
              are deleted.  Other carriage returns are handled as specified by
              the  -r option.  Unicode formatting characters, such as the Byte
              Order Mark, are sent to the terminal.  Text which is  overstruck
              or underlined can be searched for if neither -u nor -U is in ef‐
              fect.

              See also the --proc-backspace, --proc-tab, and --proc-return op‐
              tions.

       -V or --version
              Displays the version number of less.

       -w or --hilite-unread
              Temporarily  highlights  the  first  "new"  line after a forward
              movement of a full page.  The first "new" line is the line imme‐
              diately  following  the  line  previously  at  the bottom of the
              screen.  Also highlights the target line after a g or p command.
              The  highlight is removed at the next command which causes move‐
              ment.  If the --status-line option is in effect, the entire line
              (the  width  of the screen) is highlighted.  Otherwise, only the
              text in the line is highlighted, unless the -J option is in  ef‐
              fect, in which case only the status column is highlighted.

       -W or --HILITE-UNREAD
              Like -w, but temporarily highlights the first new line after any
              forward movement command larger than one line.

       -xn,... or --tabs=n,...
              Sets tab stops.  If only one n is specified, tab stops  are  set
              at  multiples  of n.  If multiple values separated by commas are
              specified, tab stops are set at those positions, and  then  con‐
              tinue  with  the  same  spacing  as  the last two.  For example,
              "-x9,17" will set tabs at positions 9, 17, 25, 33, etc.  The de‐
              fault for n is 8.

       -X or --no-init
              Disables sending the termcap initialization and deinitialization
              strings to the terminal.  This is  sometimes  desirable  if  the
              deinitialization  string does something unnecessary, like clear‐
              ing the screen.

       -yn or --max-forw-scroll=n
              Specifies a maximum number of lines to scroll forward.  If it is
              necessary to scroll forward more than n lines, the screen is re‐
              painted instead.  The -c or -C option may  be  used  to  repaint
              from  the top of the screen if desired.  By default, any forward
              movement causes scrolling.

       -zn or --window=n or -n
              Changes the default scrolling window size to n lines.   The  de‐
              fault  is  one screenful.  The z and w commands can also be used
              to change the window size.  The "z" may be omitted for  compati‐
              bility  with some versions of more(1).  If the number n is nega‐
              tive, it indicates n lines less than the  current  screen  size.
              For  example, if the screen is 24 lines, -z-4 sets the scrolling
              window to 20 lines.  If the screen is resized to 40  lines,  the
              scrolling window automatically changes to 36 lines.

       -"cc or --quotes=cc
              Changes  the  filename quoting character.  This may be necessary
              if you are trying to name a file which contains both spaces  and
              quote  characters.  Followed by a single character, this changes
              the quote character to that character.  Filenames  containing  a
              space should then be surrounded by that character rather than by
              double quotes.  Followed by two  characters,  changes  the  open
              quote  to the first character, and the close quote to the second
              character.  Filenames containing a space should then be preceded
              by  the  open  quote  character  and followed by the close quote
              character.  Note  that  even  after  the  quote  characters  are
              changed,  this  option  remains  -" (a dash followed by a double
              quote).

       -~ or --tilde
              Normally lines after end of file are displayed as a single tilde
              (~).  This option causes lines after end of file to be displayed
              as blank lines.

       -# or --shift
              Specifies the default number of positions to scroll horizontally
              in  the RIGHTARROW and LEFTARROW commands.  If the number speci‐
              fied is zero, it sets the default number  of  positions  to  one
              half of the screen width.  Alternately, the number may be speci‐
              fied as a fraction of the width of the screen, starting  with  a
              decimal  point:  .5  is  half  of  the screen width, .3 is three
              tenths of the screen width, and so on.  If the number is  speci‐
              fied as a fraction, the actual number of scroll positions is re‐
              calculated if the terminal window is resized.

       --exit-follow-on-close
              When using the "F" command on a pipe,  less  will  automatically
              stop  waiting  for  more data when the input side of the pipe is
              closed.

       --file-size
              If --file-size is specified, less will determine the size of the
              file  immediately  after opening the file.  Then the "=" command
              will display the number of lines in the file.  Normally this  is
              not  done, because it can be slow if the input file is non-seek‐
              able (such as a pipe) and is large.

       --follow-name
              Normally, if the input file is renamed while an F command is ex‐
              ecuting, less will continue to display the contents of the orig‐
              inal file despite its name change.  If --follow-name  is  speci‐
              fied,  during an F command less will periodically attempt to re‐
              open the file by name.  If the reopen succeeds and the file is a
              different  file  from  the original (which means that a new file
              has been created with the same name as  the  original  (now  re‐
              named) file), less will display the contents of that new file.

       --header=N[,M]
              Sets  the  number  of  header lines and columns displayed on the
              screen.  The value may be of the form "N,M" where N  and  M  are
              integers, to set the header lines to N and the header columns to
              M, or it may be a single integer "N" which sets the header lines
              to  N  and  the  header columns to zero, or it may be ",M" which
              sets the header columns to M and the header lines to zero.  When
              N is nonzero, the first N lines at the top of the screen are re‐
              placed with the first N lines of the file,  regardless  of  what
              part of the file are being viewed.  When M is nonzero, the char‐
              acters displayed at the beginning of each line are replaced with
              the first M characters of the line, even if the rest of the line
              is scrolled horizontally.  If either N or M is zero, less  stops
              displaying header lines or columns, respectively.  (Note that it
              may be necessary to change the setting of the -j option  to  en‐
              sure  that  the  target  line  is  not  obscured  by  the header
              line(s).)

       --incsearch
              Subsequent search commands will be "incremental"; that is,  less
              will  advance  to the next line containing the search pattern as
              each character of the pattern is typed in.

       --intr=c
              Use the character c instead of ^X to interrupt a read  when  the
              "Waiting  for  data"  message  is displayed.  c must be an ASCII
              character; that is, one with a value between 1  and  127  inclu‐
              sive.   A  caret  followed  by a single character can be used to
              specify a control character.

       --line-num-width=n
              Sets the minimum width of the line number field when the -N  op‐
              tion is in effect to n characters.  The default is 7.

       --modelines=n
              Before  displaying  a  file, less will read the first n lines to
              try to find a vim-compatible modeline.  If n is zero, less  does
              not try to find modelines.  By using a modeline, the file itself
              can specify the tab stops that should be used when viewing it.

              A modeline contains, anywhere in the line, a program name ("vi",
              "vim",  "ex", or "less"), followed by a colon, possibly followed
              by the word "set", and finally followed by zero or  more  option
              settings.   If the word "set" is used, option settings are sepa‐
              rated by spaces, and end at the first colon.  If the word  "set"
              is  not  used, option settings may be separated by either spaces
              or colons.  The word "set" is required if the  program  name  is
              "less"  but  optional  if any of the other three names are used.
              If any option setting is of the form "tabstop=n" or "ts=n", then
              tab  stops  are automatically set as if --tabs=n had been given.
              See the --tabs description for acceptable values of n.

       --mouse
              Enables mouse input: scrolling the mouse wheel down  moves  for‐
              ward  in  the file, scrolling the mouse wheel up moves backwards
              in the file, and clicking the mouse sets the  "#"  mark  to  the
              line  where the mouse is clicked.  The number of lines to scroll
              when the wheel is moved can be set by the --wheel-lines  option.
              Mouse  input works only on terminals which support X11 mouse re‐
              porting, and on the Windows version of less.

       --MOUSE
              Like --mouse, except the direction scrolled on mouse wheel move‐
              ment is reversed.

       --no-keypad
              Disables  sending the keypad initialization and deinitialization
              strings to the terminal.  This is sometimes useful if the keypad
              strings make the numeric keypad behave in an undesirable manner.

       --no-histdups
              This  option  changes the behavior so that if a search string or
              file name is typed in, and the same string  is  already  in  the
              history list, the existing copy is removed from the history list
              before the new one is added.  Thus, a given string  will  appear
              only  once  in  the history list.  Normally, a string may appear
              multiple times.

       --no-number-headers
              Header lines (defined via the --header option) are not  assigned
              line numbers.  Line number 1 is assigned to the first line after
              any header lines.

       --no-search-headers
              Searches do not include header lines or header columns.

       --no-vbell
              Disables the terminal's visual bell.

       --proc-backspace
              If set, backspaces are handled as if neither the -u  option  nor
              the -U option were set.  That is, a backspace adjacent to an un‐
              derscore causes text to be displayed in underline  mode,  and  a
              backspace  between  identical  characters  cause text to be dis‐
              played in boldface mode.  This option overrides the  -u  and  -U
              options,  so  that display of backspaces can be controlled sepa‐
              rate from tabs and carriage returns.  If not set, backspace dis‐
              play is controlled by the -u and -U options.

       --PROC-BACKSPACE
              If  set,  backspaces  are  handled as if the -U option were set;
              that is backspaces are treated as control characters.

       --proc-return
              If set, carriage returns are handled as if neither the -u option
              nor  the -U option were set.  That is, a carriage return immedi‐
              ately before a newline is deleted.  This option overrides the -u
              and  -U options, so that display of carriage returns can be con‐
              trolled separate from that of backspaces and tabs.  If not  set,
              carriage return display is controlled by the -u and -U options.

       --PROC-RETURN
              If  set,  carriage  returns are handled as if the -U option were
              set; that is carriage returns are treated as control characters.

       --proc-tab
              If set, tabs are handled as if the -U option were not set.  That
              is,  tabs  are expanded to spaces.  This option overrides the -U
              option, so that display of tabs can be controlled separate  from
              that  of  backspaces and carriage returns.  If not set, tab dis‐
              play is controlled by the -U options.

       --PROC-TAB
              If set, tabs are handled as if the -U option were set;  that  is
              tabs are treated as control characters.

       --redraw-on-quit
              When  quitting,  after  sending  the  terminal  deinitialization
              string, redraws the entire last screen.  On terminals whose ter‐
              minal deinitialization string causes the terminal to switch from
              an alternate screen, this makes the last screenful of  the  cur‐
              rent file remain visible after less has quit.

       --rscroll=c
              This  option changes the character used to mark truncated lines.
              It may begin with a two-character attribute indicator like LESS‐
              BINFMT  does.   If  there is no attribute indicator, standout is
              used.  If set to "-", truncated lines are not marked.

       --save-marks
              Save marks in the history file, so  marks  are  retained  across
              different invocations of less.

       --search-options=...
              Sets  default search modifiers.  The value is a string of one or
              more of the characters E, F, K, N, R or W.  Setting any of these
              has  the same effect as typing that control character at the be‐
              ginning of every search pattern.  For example, setting --search-
              options=W  is  the  same  as typing ^W at the beginning of every
              pattern.  The value may also contain a digit between  1  and  5,
              which has the same effect as typing ^S followed by that digit at
              the beginning of every search pattern.  The value  "-"  disables
              all default search modifiers.

       --show-preproc-errors
              If a preprocessor produces data, then exits with a non-zero exit
              code, less will display a warning.

       --status-col-width=n
              Sets the width of the status column when the -J option is in ef‐
              fect.  The default is 2 characters.

       --status-line
              If  a line is marked, the entire line (rather than just the sta‐
              tus column) is highlighted.  Also lines highlighted due  to  the
              -w option will have the entire line highlighted.  If --use-color
              is set, the line is colored rather than highlighted.

       --use-backslash
              This option changes the interpretations of options which  follow
              this one.  After the --use-backslash option, any backslash in an
              option string is removed and the following  character  is  taken
              literally.   This  allows a dollar sign to be included in option
              strings.

       --use-color
              Enables colored text in various places.  The -D  option  can  be
              used  to change the colors.  Colored text works only if the ter‐
              minal supports ANSI color escape sequences (as  defined  in  EC‐
              MA-48 SGR; see
              https://www.ecma-international.org/publications-and-
              standards/standards/ecma-48).

       --wheel-lines=n
              Set the number of lines  to  scroll  when  the  mouse  wheel  is
              scrolled  and  the  --mouse or --MOUSE option is in effect.  The
              default is 1 line.

       --wordwrap
              When the -S option is not in use, wrap each line at a  space  or
              tab  if possible, so that a word is not split between two lines.
              The default is to wrap at any character.

       --     A command line argument of "--" marks the end  of  option  argu‐
              ments.   Any  arguments  following this are interpreted as file‐
              names.  This can be useful when viewing a file whose name begins
              with a "-" or "+".

       +      If  a  command  line option begins with +, the remainder of that
              option is taken to be an initial command to less.  For  example,
              +G  tells  less  to start at the end of the file rather than the
              beginning, and +/xyz tells it to start at the  first  occurrence
              of  "xyz"  in  the file.  As a special case, +<number> acts like
              +<number>g; that is, it starts the display at the specified line
              number  (however,  see  the caveat under the "g" command above).
              If the option starts with ++, the initial command applies to ev‐
              ery  file  being  viewed, not just the first one.  The + command
              described previously may also be used to set (or change) an ini‐
              tial command for every file.

LINE EDITING
       When  entering a command line at the bottom of the screen (for example,
       a filename for the :e command, or the pattern for  a  search  command),
       certain keys can be used to manipulate the command line.  Most commands
       have an alternate form in [ brackets ] which can be used if a key  does
       not  exist  on  a  particular keyboard.  (Note that the forms beginning
       with ESC do not work in some MS-DOS and Windows systems because ESC  is
       the  line  erase  character.)  Any of these special keys may be entered
       literally by preceding it with the "literal" character,  either  ^V  or
       ^A.   A  backslash itself may also be entered literally by entering two
       backslashes.

       LEFTARROW [ ESC-h ]
              Move the cursor one space to the left.

       RIGHTARROW [ ESC-l ]
              Move the cursor one space to the right.

       ^LEFTARROW [ ESC-b or ESC-LEFTARROW ]
              (That is, CONTROL and LEFTARROW simultaneously.)  Move the  cur‐
              sor one word to the left.

       ^RIGHTARROW [ ESC-w or ESC-RIGHTARROW ]
              (That is, CONTROL and RIGHTARROW simultaneously.)  Move the cur‐
              sor one word to the right.

       HOME [ ESC-0 ]
              Move the cursor to the beginning of the line.

       END [ ESC-$ ]
              Move the cursor to the end of the line.

       BACKSPACE
              Delete the character to the left of the cursor,  or  cancel  the
              command if the command line is empty.

       DELETE or [ ESC-x ]
              Delete the character under the cursor.

       ^BACKSPACE [ ESC-BACKSPACE ]
              (That  is,  CONTROL  and  BACKSPACE simultaneously.)  Delete the
              word to the left of the cursor.

       ^DELETE [ ESC-X or ESC-DELETE ]
              (That is, CONTROL and DELETE simultaneously.)  Delete  the  word
              under the cursor.

       UPARROW [ ESC-k ]
              Retrieve  the  previous  command  line.  If you first enter some
              text and then press UPARROW, it will retrieve the previous  com‐
              mand which begins with that text.

       DOWNARROW [ ESC-j ]
              Retrieve  the  next  command line.  If you first enter some text
              and then press DOWNARROW, it  will  retrieve  the  next  command
              which begins with that text.

       TAB    Complete  the partial filename to the left of the cursor.  If it
              matches more than one filename, the first match is entered  into
              the  command  line.   Repeated  TABs  will  cycle thru the other
              matching filenames.  If the completed filename is a directory, a
              "/"  is  appended to the filename.  (On MS-DOS systems, a "\" is
              appended.)  The environment variable LESSSEPARATOR can  be  used
              to specify a different character to append to a directory name.

       BACKTAB [ ESC-TAB ]
              Like, TAB, but cycles in the reverse direction thru the matching
              filenames.

       ^L     Complete the partial filename to the left of the cursor.  If  it
              matches more than one filename, all matches are entered into the
              command line (if they fit).

       ^U (Unix and OS/2) or ESC (MS-DOS)
              Delete the entire command line, or cancel  the  command  if  the
              command line is empty.  If you have changed your line-kill char‐
              acter in Unix to something other than ^U, that character is used
              instead of ^U.

       ^G     Delete the entire command line and return to the main prompt.

KEY BINDINGS
       You  may  define  your  own  less commands by creating a lesskey source
       file.  This file specifies a set of command keys and an action  associ‐
       ated  with  each  key.   You may also change the line-editing keys (see
       LINE EDITING), and set environment variables used  by  less.   See  the
       lesskey(1) manual page for details about the file format.

       If  the  environment  variable  LESSKEYIN is set, less uses that as the
       name of the lesskey source file.  Otherwise, less looks in  a  standard
       place  for  the  lesskey source file: On Unix systems, less looks for a
       lesskey  file   called   "$XDG_CONFIG_HOME/lesskey"   or   "$HOME/.con‐
       fig/lesskey"  or "$HOME/.lesskey".  On MS-DOS and Windows systems, less
       looks for a lesskey file called "$HOME/_lesskey",  and  if  it  is  not
       found there, then looks for a lesskey file called "_lesskey" in any di‐
       rectory specified in the PATH environment variable.  On  OS/2  systems,
       less  looks for a lesskey file called "$HOME/lesskey.ini", and if it is
       not found, then looks for a lesskey file called  "lesskey.ini"  in  any
       directory  specified  in  the  INIT environment variable, and if it not
       found there, then looks for a lesskey file called "lesskey.ini" in  any
       directory specified in the PATH environment variable.

       A  system-wide  lesskey  source  file may also be set up to provide key
       bindings.  If a key is defined in both a local lesskey file and in  the
       system-wide  file,  key bindings in the local file take precedence over
       those  in  the  system-wide  file.    If   the   environment   variable
       LESSKEYIN_SYSTEM  is set, less uses that as the name of the system-wide
       lesskey file.  Otherwise, less looks in a standard place for  the  sys‐
       tem-wide lesskey file: On Unix systems, the system-wide lesskey file is
       /usr/local/etc/syslesskey.  (However, if less was built with a  differ‐
       ent  sysconf directory than /usr/local/etc, that directory is where the
       sysless file is found.)  On MS-DOS and Windows systems, the system-wide
       lesskey  file  is  c:\_syslesskey.   On  OS/2  systems, the system-wide
       lesskey file is c:\syslesskey.ini.

       Previous versions of less (before v582) used lesskey files with a bina‐
       ry  format,  produced by the lesskey program. It is no longer necessary
       to use the lesskey program.

INPUT PREPROCESSOR
       You may define an "input preprocessor" for less.  Before less  opens  a
       file, it first gives your input preprocessor a chance to modify the way
       the contents of the file are displayed.  An input preprocessor is  sim‐
       ply  an executable program (or shell script), which writes the contents
       of the file to a different file, called the replacement file.  The con‐
       tents  of  the replacement file are then displayed in place of the con‐
       tents of the original file.  However, it will appear to the user as  if
       the  original  file  is opened; that is, less will display the original
       filename as the name of the current file.

       An input preprocessor receives one command line argument, the  original
       filename,  as  entered  by  the user.  It should create the replacement
       file, and when finished, print the name of the replacement file to  its
       standard  output.  If the input preprocessor does not output a replace‐
       ment filename, less uses the original file, as normal.  The input  pre‐
       processor  is not called when viewing standard input.  To set up an in‐
       put preprocessor, set the LESSOPEN environment variable  to  a  command
       line  which  will  invoke  your  input preprocessor.  This command line
       should include one occurrence of the string "%s",  which  will  be  re‐
       placed by the filename when the input preprocessor command is invoked.

       When less closes a file opened in such a way, it will call another pro‐
       gram, called the input postprocessor, which  may  perform  any  desired
       clean-up  action  (such  as  deleting  the  replacement file created by
       LESSOPEN).  This program receives two command line arguments, the orig‐
       inal  filename  as entered by the user, and the name of the replacement
       file.  To set up an input postprocessor, set the LESSCLOSE  environment
       variable  to a command line which will invoke your input postprocessor.
       It may include two occurrences of the string "%s";  the  first  is  re‐
       placed  with the original name of the file and the second with the name
       of the replacement file, which was output by LESSOPEN.

       For example, on many Unix systems, these two scripts will allow you  to
       keep files in compressed format, but still let less view them directly:

       lessopen.sh:
            #! /bin/sh
            case "$1" in
            *.Z) TEMPFILE=$(mktemp)
                 uncompress -c $1  >$TEMPFILE  2>/dev/null
                 if [ -s $TEMPFILE ]; then
                      echo $TEMPFILE
                 else
                      rm -f $TEMPFILE
                 fi
                 ;;
            esac

       lessclose.sh:
            #! /bin/sh
            rm $2

       To  use these scripts, put them both where they can be executed and set
       LESSOPEN="lessopen.sh %s",  and  LESSCLOSE="lessclose.sh %s %s".   More
       complex  LESSOPEN  and LESSCLOSE scripts may be written to accept other
       types of compressed files, and so on.

       It is also possible to set up an input preprocessor to  pipe  the  file
       data  directly to less, rather than putting the data into a replacement
       file.  This avoids the need to decompress the entire file before start‐
       ing to view it.  An input preprocessor that works this way is called an
       input pipe.  An input pipe, instead of writing the name of  a  replace‐
       ment file on its standard output, writes the entire contents of the re‐
       placement file on its standard output.  If  the  input  pipe  does  not
       write  any characters on its standard output, then there is no replace‐
       ment file and less uses the original file, as normal.  To use an  input
       pipe,  make  the first character in the LESSOPEN environment variable a
       vertical bar (|) to signify that the input  preprocessor  is  an  input
       pipe.   As  with  non-pipe input preprocessors, the command string must
       contain one occurrence of %s, which is replaced with  the  filename  of
       the input file.

       For  example, on many Unix systems, this script will work like the pre‐
       vious example scripts:

       lesspipe.sh:
            #! /bin/sh
            case "$1" in
            *.Z) uncompress -c $1  2>/dev/null
                 ;;
            *)   exit 1
                 ;;
            esac
            exit $?

       To  use  this  script,  put  it  where  it  can  be  executed  and  set
       LESSOPEN="|lesspipe.sh %s".

       Note that a preprocessor cannot output an empty file, since that is in‐
       terpreted as meaning there is no replacement, and the original file  is
       used.   To  avoid  this, if LESSOPEN starts with two vertical bars, the
       exit status of the script determines the behavior when  the  output  is
       empty.   If  the output is empty and the exit status is zero, the empty
       output is considered to be replacement text.  If the  output  is  empty
       and the exit status is nonzero, the original file is used.  For compat‐
       ibility with previous versions of less, if LESSOPEN  starts  with  only
       one vertical bar, the exit status of the preprocessor is ignored.

       When  an input pipe is used, a LESSCLOSE postprocessor can be used, but
       it is usually not necessary since there is no replacement file to clean
       up.   In  this  case, the replacement file name passed to the LESSCLOSE
       postprocessor is "-".

       For compatibility with previous versions of less, the input  preproces‐
       sor or pipe is not used if less is viewing standard input.  However, if
       the first character of LESSOPEN is a dash (-), the  input  preprocessor
       is  used  on  standard input as well as other files.  In this case, the
       dash is not considered to be part  of  the  preprocessor  command.   If
       standard input is being viewed, the input preprocessor is passed a file
       name consisting of a single dash.  Similarly, if the first two  charac‐
       ters  of  LESSOPEN  are vertical bar and dash (|-) or two vertical bars
       and a dash (||-), the input pipe is used on standard input as  well  as
       other files.  Again, in this case the dash is not considered to be part
       of the input pipe command.

NATIONAL CHARACTER SETS
       There are three types of characters in the input file:

       normal characters
              can be displayed directly to the screen.

       control characters
              should not be displayed directly, but are expected to  be  found
              in ordinary text files (such as backspace and tab).

       binary characters
              should  not  be  displayed  directly  and are not expected to be
              found in text files.

       A "character set" is simply a description of which characters are to be
       considered  normal,  control,  and binary.  The LESSCHARSET environment
       variable may be used to select a character set.   Possible  values  for
       LESSCHARSET are:

       ascii  BS,  TAB, NL, CR, and formfeed are control characters, all chars
              with values between 32 and 126 are normal, and  all  others  are
              binary.

       iso8859
              Selects  an  ISO 8859 character set.  This is the same as ASCII,
              except characters between 160 and  255  are  treated  as  normal
              characters.

       latin1 Same as iso8859.

       latin9 Same as iso8859.

       dos    Selects a character set appropriate for MS-DOS.

       ebcdic Selects an EBCDIC character set.

       IBM-1047
              Selects  an  EBCDIC  character set used by OS/390 Unix Services.
              This is the EBCDIC analogue of latin1.  You get similar  results
              by setting either LESSCHARSET=IBM-1047 or LC_CTYPE=en_US in your
              environment.

       koi8-r Selects a Russian character set.

       next   Selects a character set appropriate for NeXT computers.

       utf-8  Selects the UTF-8 encoding  of  the  ISO  10646  character  set.
              UTF-8  is  special  in that it supports multi-byte characters in
              the input file.  It is the only character set that supports mul‐
              ti-byte characters.

       windows
              Selects  a  character  set appropriate for Microsoft Windows (cp
              1251).

       In rare cases, it may be desired to tailor less to use a character  set
       other  than the ones definable by LESSCHARSET.  In this case, the envi‐
       ronment variable LESSCHARDEF can be used to define a character set.  It
       should be set to a string where each character in the string represents
       one character in the character set.  The character "." is  used  for  a
       normal  character, "c" for control, and "b" for binary.  A decimal num‐
       ber may be used for repetition.   For  example,  "bccc4b."  would  mean
       character  0 is binary, 1, 2 and 3 are control, 4, 5, 6 and 7 are bina‐
       ry, and 8 is normal.  All characters after the last are taken to be the
       same  as  the last, so characters 9 through 255 would be normal.  (This
       is an example, and does not necessarily represent  any  real  character
       set.)

       This  table  shows the value of LESSCHARDEF which is equivalent to each
       of the possible values for LESSCHARSET:


            ascii      8bcccbcc18b95.b
            dos        8bcccbcc12bc5b95.b.
            ebcdic     5bc6bcc7bcc41b.9b7.9b5.b..8b6.10b6.b9.7b
                       9.8b8.17b3.3b9.7b9.8b8.6b10.b.b.b.
            IBM-1047   4cbcbc3b9cbccbccbb4c6bcc5b3cbbc4bc4bccbc
                       191.b
            iso8859    8bcccbcc18b95.33b.
            koi8-r     8bcccbcc18b95.b128.
            latin1     8bcccbcc18b95.33b.
            next       8bcccbcc18b95.bb125.bb

       If neither LESSCHARSET nor LESSCHARDEF is set, but any of  the  strings
       "UTF-8",  "UTF8", "utf-8" or "utf8" is found in the LC_ALL, LC_CTYPE or
       LANG environment variables, then the default character set is utf-8.

       If that string is not found, but your system supports the setlocale in‐
       terface,  less will use setlocale to determine the character set.  set‐
       locale is controlled by setting the LANG or LC_CTYPE environment  vari‐
       ables.

       Finally,  if the setlocale interface is also not available, the default
       character set is latin1.

       Control and  binary  characters  are  displayed  in  standout  (reverse
       video).  Each such character is displayed in caret notation if possible
       (e.g. ^A for control-A).  Caret notation is used only if inverting  the
       0100 bit results in a normal printable character.  Otherwise, the char‐
       acter is displayed as a hex number in angle brackets.  This format  can
       be  changed by setting the LESSBINFMT environment variable.  LESSBINFMT
       may begin with a "*" and one character to select the display attribute:
       "*k"  is  blinking, "*d" is bold, "*u" is underlined, "*s" is standout,
       and "*n" is normal.  If LESSBINFMT does not begin with  a  "*",  normal
       attribute  is  assumed.   The remainder of LESSBINFMT is a string which
       may include one printf-style escape sequence (a % followed by x, X,  o,
       d,  etc.).   For  example, if LESSBINFMT is "*u[%x]", binary characters
       are displayed in underlined hexadecimal surrounded  by  brackets.   The
       default  if no LESSBINFMT is specified is "*s<%02X>".  Warning: the re‐
       sult of expanding the character via LESSBINFMT must  be  less  than  31
       characters.

       When the character set is utf-8, the LESSUTFBINFMT environment variable
       acts similarly to LESSBINFMT but it applies to Unicode code points that
       were  successfully  decoded but are unsuitable for display (e.g., unas‐
       signed code points).  Its default  value  is  "<U+%04lX>".   Note  that
       LESSUTFBINFMT  and  LESSBINFMT  share  their  display attribute setting
       ("*x") so specifying one will affect both; LESSUTFBINFMT is read  after
       LESSBINFMT  so  its  setting,  if any, will have priority.  Problematic
       octets in a UTF-8 file (octets of a truncated  sequence,  octets  of  a
       complete  but  non-shortest  form  sequence,  invalid octets, and stray
       trailing octets) are displayed individually using LESSBINFMT so  as  to
       facilitate diagnostic of how the UTF-8 file is ill-formed.

       When  the  character set is utf-8, in rare cases it may be desirable to
       override the Unicode definition of the type of certain characters.  For
       example,  characters in a Private Use Area are normally treated as con‐
       trol characters, but if you are using  a  custom  font  with  printable
       characters  in  that  range,  it may be desirable to tell less to treat
       such characters as printable.  This can be done by setting the  LESSUT‐
       FCHARDEF  environment  variable  to a comma-separated list of character
       type definitions.  Each character type definition  consists  of  either
       one  hexadecimal codepoint or a pair of codepoints separated by a dash,
       followed by a colon and a type character.  Each  hexadecimal  codepoint
       may  optionally  be preceded by a "U" or "U+".  If a pair of codepoints
       is given, the type is set for all characters  inclusively  between  the
       two  values.   If  there are multiple comma-separated codepoint values,
       they must be in ascending numerical order.  The type character  may  be
       one of:

              p      A normal printable character.

              w      A wide (2-space) printable character.

              b      A binary (non-printable) character.

              c      A composing (zero width) character.

       For example, setting LESSUTFCHARDEF to

               E000-F8FF:p,F0000-FFFFD:p,100000-10FFFD:p

       would make all Private Use Area characters be treated as printable.

PROMPTS
       The  -P option allows you to tailor the prompt to your preference.  The
       string given to the -P option replaces  the  specified  prompt  string.
       Certain characters in the string are interpreted specially.  The prompt
       mechanism is rather complicated to provide flexibility, but  the  ordi‐
       nary  user need not understand the details of constructing personalized
       prompt strings.

       A percent sign followed by a single character is expanded according  to
       what  the  following  character is.  (References to the input file size
       below refer to the preprocessed size, if an input preprocessor is being
       used.)

       %bX    Replaced  by the byte offset into the current input file.  The b
              is followed by a single character (shown as X above) which spec‐
              ifies  the line whose byte offset is to be used.  If the charac‐
              ter is a "t", the byte offset of the top line in the display  is
              used, an "m" means use the middle line, a "b" means use the bot‐
              tom line, a "B" means use the line just after the  bottom  line,
              and  a  "j"  means use the "target" line, as specified by the -j
              option.

       %B     Replaced by the size of the current input file.

       %c     Replaced by the column number of the text appearing in the first
              column of the screen.

       %dX    Replaced  by  the  page number of a line in the input file.  The
              line to be used is determined by the X, as with the %b option.

       %D     Replaced by the number of pages in the input  file,  or  equiva‐
              lently, the page number of the last line in the input file.

       %E     Replaced  by the name of the editor (from the VISUAL environment
              variable, or the EDITOR environment variable if  VISUAL  is  not
              defined).  See the discussion of the LESSEDIT feature below.

       %f     Replaced by the name of the current input file.

       %F     Replaced  by the last component of the name of the current input
              file.

       %g     Replaced by the shell-escaped name of the  current  input  file.
              This  is useful when the expanded string will be used in a shell
              command, such as in LESSEDIT.

       %i     Replaced by the index of the current file in the list  of  input
              files.

       %lX    Replaced  by  the  line number of a line in the input file.  The
              line to be used is determined by the X, as with the %b option.

       %L     Replaced by the line number of the last line in the input file.

       %m     Replaced by the total number of input files.

       %pX    Replaced by the percent into the current input  file,  based  on
              byte  offsets.  The line used is determined by the X as with the
              %b option.

       %PX    Replaced by the percent into the current input  file,  based  on
              line  numbers.  The line used is determined by the X as with the
              %b option.

       %s     Same as %B.

       %t     Causes any trailing spaces to be removed.  Usually used  at  the
              end of the string, but may appear anywhere.

       %T     Normally  expands  to the word "file".  However if viewing files
              via a tags list using the -t option,  it  expands  to  the  word
              "tag".

       %x     Replaced by the name of the next input file in the list.

       If any item is unknown (for example, the file size if input is a pipe),
       a question mark is printed instead.

       The format of the prompt string can be  changed  depending  on  certain
       conditions.   A  question mark followed by a single character acts like
       an "IF": depending on the following character, a condition is  evaluat‐
       ed.   If  the  condition is true, any characters following the question
       mark and condition character, up to  a  period,  are  included  in  the
       prompt.   If  the condition is false, such characters are not included.
       A colon appearing between the question mark and the period can be  used
       to establish an "ELSE": any characters between the colon and the period
       are included in the string if and only if the IF  condition  is  false.
       Condition characters (which follow a question mark) may be:

       ?a     True if any characters have been included in the prompt so far.

       ?bX    True if the byte offset of the specified line is known.

       ?B     True if the size of current input file is known.

       ?c     True if the text is horizontally shifted (%c is not zero).

       ?dX    True if the page number of the specified line is known.

       ?e     True if at end-of-file.

       ?f     True  if  there is an input filename (that is, if input is not a
              pipe).

       ?lX    True if the line number of the specified line is known.

       ?L     True if the line number of the last line in the file is known.

       ?m     True if there is more than one input file.

       ?n     True if this is the first prompt in a new input file.

       ?pX    True if the percent into the current input file, based  on  byte
              offsets, of the specified line is known.

       ?PX    True  if  the percent into the current input file, based on line
              numbers, of the specified line is known.

       ?s     Same as "?B".

       ?x     True if there is a next input file (that is, if the current  in‐
              put file is not the last one).

       Any characters other than the special ones (question mark, colon, peri‐
       od, percent, and backslash) become literally part of the  prompt.   Any
       of  the  special  characters may be included in the prompt literally by
       preceding it with a backslash.

       Some examples:

       ?f%f:Standard input.

       This prompt prints the filename, if known; otherwise the string  "Stan‐
       dard input".

       ?f%f .?ltLine %lt:?pt%pt\%:?btByte %bt:-...

       This  prompt  would print the filename, if known.  The filename is fol‐
       lowed by the line number, if known, otherwise  the  percent  if  known,
       otherwise the byte offset if known.  Otherwise, a dash is printed.  No‐
       tice how each question mark has a matching period, and how the %  after
       the %pt is included literally by escaping it with a backslash.

       ?n?f%f .?m(%T %i of %m) ..?e(END) ?x- Next\: %x..%t";

       This  prints  the  filename if this is the first prompt in a file, fol‐
       lowed by the "file N of N" message if there  is  more  than  one  input
       file.   Then,  if  we are at end-of-file, the string "(END)" is printed
       followed by the name of the next file, if there is one.   Finally,  any
       trailing spaces are truncated.  This is the default prompt.  For refer‐
       ence, here are the defaults for the other two prompts (-m  and  -M  re‐
       spectively).  Each is broken into two lines here for readability only.

       ?n?f%f .?m(%T %i of %m) ..?e(END) ?x- Next\: %x.:
               ?pB%pB\%:byte %bB?s/%s...%t

       ?f%f .?n?m(%T %i of %m) ..?ltlines %lt-%lb?L/%L. :
               byte %bB?s/%s. .?e(END) ?x- Next\: %x.:?pB%pB\%..%t

       And here is the default message produced by the = command:

       ?f%f .?m(%T %i of %m) .?ltlines %lt-%lb?L/%L. .
               byte %bB?s/%s. ?e(END) :?pB%pB\%..%t

       The  prompt expansion features are also used for another purpose: if an
       environment variable LESSEDIT is defined, it is used as the command  to
       be  executed when the v command is invoked.  The LESSEDIT string is ex‐
       panded in the same way as the prompt strings.  The  default  value  for
       LESSEDIT is:

               %E ?lm+%lm. %g

       Note that this expands to the editor name, followed by a + and the line
       number, followed by the shell-escaped file name.  If your  editor  does
       not  accept the "+linenumber" syntax, or has other differences in invo‐
       cation syntax, the LESSEDIT variable can be changed to modify this  de‐
       fault.

SECURITY
       When  the  environment  variable LESSSECURE is set to 1, less runs in a
       "secure" mode.  This means these features are disabled:

              !      the shell command

              #      the pshell command

              |      the pipe command

              :e     the examine command.

              v      the editing command

              s  -o  log files

              -k     use of lesskey files

              -t     use of tags files

                     metacharacters in filenames, such as *

                     filename completion (TAB, ^L)

                     history file

       Less can also be compiled to be permanently in "secure" mode.

COMPATIBILITY WITH MORE
       If the environment variable LESS_IS_MORE is set to 1, or if the program
       is  invoked via a file link named "more", less behaves (mostly) in con‐
       formance with the POSIX more(1) command specification.  In  this  mode,
       less behaves differently in these ways:

       The -e option works differently.  If the -e option is not set, less be‐
       haves as if the -e option were set.  If the -e option is set, less  be‐
       haves as if the -E option were set.

       The  -m  option  works  differently.   If the -m option is not set, the
       medium prompt is used, and it is prefixed with the  string  "--More--".
       If the -m option is set, the short prompt is used.

       The  -n  option acts like the -z option.  The normal behavior of the -n
       option is unavailable in this mode.

       The parameter to the -p option is taken to be  a  less  command  rather
       than a search pattern.

       The  LESS  environment  variable  is  ignored, and the MORE environment
       variable is used in its place.

ENVIRONMENT VARIABLES
       Environment variables may be specified either in the system environment
       as  usual,  or  in a lesskey(1) file.  If environment variables are de‐
       fined in more than one place, variables defined in a local lesskey file
       take precedence over variables defined in the system environment, which
       take precedence over variables defined in the system-wide lesskey file.

       COLUMNS
              Sets the number of columns on the screen.  Takes precedence over
              the  number  of columns specified by the TERM variable.  (But if
              you  have  a  windowing  system  which  supports  TIOCGWINSZ  or
              WIOCGETD,  the  window  system's  idea  of the screen size takes
              precedence over the LINES and COLUMNS environment variables.)

       EDITOR The name of the editor (used for the v command).

       HOME   Name of the user's home directory (used to find a  lesskey  file
              on Unix and OS/2 systems).

       HOMEDRIVE, HOMEPATH
              Concatenation  of  the  HOMEDRIVE and HOMEPATH environment vari‐
              ables is the name of the user's home directory if the HOME vari‐
              able is not set (only in the Windows version).

       INIT   Name  of  the user's init directory (used to find a lesskey file
              on OS/2 systems).

       LANG   Language for determining the character set.

       LC_CTYPE
              Language for determining the character set.

       LESS   Options which are passed to less automatically.

       LESSANSIENDCHARS
              Characters which may end an ANSI color escape sequence  (default
              "m").

       LESSANSIMIDCHARS
              Characters  which  may  appear between the ESC character and the
              end  character  in  an  ANSI  color  escape  sequence   (default
              "0123456789:;[?!"'#%()*+ ".

       LESSBINFMT
              Format for displaying non-printable, non-control characters.

       LESSCHARDEF
              Defines a character set.

       LESSCHARSET
              Selects a predefined character set.

       LESSCLOSE
              Command line to invoke the (optional) input-postprocessor.

       LESSECHO
              Name of the lessecho program (default "lessecho").  The lessecho
              program is needed to expand metacharacters, such as * and ?,  in
              filenames on Unix systems.

       LESSEDIT
              Editor  prototype  string (used for the v command).  See discus‐
              sion under PROMPTS.

       LESSGLOBALTAGS
              Name of the command used by the -t option to find  global  tags.
              Normally  should be set to "global" if your system has the glob‐
              al(1) command.  If not set, global tags are not used.

       LESSHISTFILE
              Name of the history file used to remember  search  commands  and
              shell  commands  between  invocations of less.  If set to "-" or
              "/dev/null", a history file is not used.  The default depends on
              the operating system, but is usually:

              Linux and Unix
                     "$XDG_STATE_HOME/lesshst" or "$HOME/.local/state/lesshst"
                     or "$XDG_DATA_HOME/lesshst" or "$HOME/.lesshst".

              Windows and MS-DOS
                     "$HOME/_lesshst".

              OS/2   "$HOME/lesshst.ini" or "$INIT/lesshst.ini".

       LESSHISTSIZE
              The maximum number of commands to save in the history file.  The
              default is 100.

       LESSKEYIN
              Name of the default lesskey source file.

       LESSKEY
              Name   of   the  default  lesskey  binary  file.  (Not  used  if
              "$LESSKEYIN" exists.)

       LESSKEYIN_SYSTEM
              Name of the default system-wide lesskey source file.

       LESSKEY_SYSTEM
              Name of the default system-wide lesskey binary file.  (Not  used
              if "$LESSKEYIN_SYSTEM" exists.)

       LESSMETACHARS
              List  of characters which are considered "metacharacters" by the
              shell.

       LESSMETAESCAPE
              Prefix which less will add before each metacharacter in  a  com‐
              mand  sent  to the shell.  If LESSMETAESCAPE is an empty string,
              commands containing metacharacters will not  be  passed  to  the
              shell.

       LESSOPEN
              Command line to invoke the (optional) input-preprocessor.

       LESSSECURE
              Runs less in "secure" mode.  See discussion under SECURITY.

       LESSSEPARATOR
              String  to  be  appended to a directory name in filename comple‐
              tion.

       LESSUTFBINFMT
              Format for displaying non-printable Unicode code points.

       LESSUTFCHARDEF
              Overrides the type of specified Unicode characters.

       LESS_COLUMNS
              Sets the number of columns on the screen.  Unlike COLUMNS, takes
              precedence  over the system's idea of the screen size, so it can
              be used to make less use less than the full  screen  width.   If
              set  to  a  negative  number, sets the number of columns used to
              this much less than the actual screen width.

       LESS_LINES
              Sets the number of lines on the  screen.   Unlike  LINES,  takes
              precedence  over the system's idea of the screen size, so it can
              be used to make less use less than the full screen  height.   If
              set  to a negative number, sets the number of lines used to this
              much less than the actual screen height.   When  set,  less  re‐
              paints the entire screen on every movement command, so scrolling
              may be slower.

       LESS_DATA_DELAY
              Duration (in milliseconds) after starting to read data from  the
              input,  after  which the "Waiting for data" message will be dis‐
              played.  The default is 4000 (4 seconds).

       LESS_IS_MORE
              Emulate the more(1) command.

       LESS_TERMCAP_xx
              Where "xx" is any two characters, overrides  the  definition  of
              the termcap "xx" capability for the terminal.

       LINES  Sets  the  number of lines on the screen.  Takes precedence over
              the number of lines specified by the TERM variable.  (But if you
              have  a  windowing system which supports TIOCGWINSZ or WIOCGETD,
              the window system's idea of the  screen  size  takes  precedence
              over the LINES and COLUMNS environment variables.)

       MORE   Options  which  are passed to less automatically when running in
              more-compatible mode.

       PATH   User's search path (used to find a lesskey file  on  MS-DOS  and
              OS/2 systems).

       SHELL  The  shell  used  to execute the ! command, as well as to expand
              filenames.

       TERM   The type of terminal on which less is being run.

       VISUAL The name of the editor (used for the v command).

       XDG_CONFIG_HOME
              Possible location of the lesskey file; see the KEY BINDINGS sec‐
              tion.

       XDG_DATA_HOME
              Possible  location  of  the history file; see the description of
              the LESSHISTFILE environment variable.

       XDG_STATE_HOME
              Possible location of the history file; see  the  description  of
              the LESSHISTFILE environment variable.

SEE ALSO
       lesskey(1), lessecho(1)

COPYRIGHT
       Copyright (C) 1984-2023  Mark Nudelman

       less  is  part of the GNU project and is free software.  You can redis‐
       tribute it and/or modify it under the terms of either (1) the GNU  Gen‐
       eral  Public  License  as published by the Free Software Foundation; or
       (2) the Less License.  See the file README in the less distribution for
       more details regarding redistribution.  You should have received a copy
       of the GNU General Public License along with the source for  less;  see
       the  file  COPYING.   If not, write to the Free Software Foundation, 59
       Temple Place, Suite 330, Boston, MA  02111-1307, USA.  You should  also
       have received a copy of the Less License; see the file LICENSE.

       less is distributed in the hope that it will be useful, but WITHOUT ANY
       WARRANTY; without even the implied warranty of MERCHANTABILITY or  FIT‐
       NESS  FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
       more details.

AUTHOR
       Mark Nudelman
       Report bugs at https://github.com/gwsw/less/issues.
       For more information, see the less homepage at
       https://greenwoodsoftware.com/less



                           Version 643: 20 Jul 2023                    LESS(1)