diff options
Diffstat (limited to 'usr.bin/file/magic.5')
| -rw-r--r-- | usr.bin/file/magic.5 | 24 |
1 files changed, 18 insertions, 6 deletions
diff --git a/usr.bin/file/magic.5 b/usr.bin/file/magic.5 index b10b7140bc12..bd1a5a5db985 100644 --- a/usr.bin/file/magic.5 +++ b/usr.bin/file/magic.5 @@ -3,14 +3,17 @@ .SH NAME magic \- file command's magic number file .SH DESCRIPTION -The -.IR file (1) +This manual page documents the format of the magic file as +used by the +.BR file (1) +command, version 3.22. The +.B file command identifies the type of a file using, among other tests, a test for whether the file begins with a certain .IR "magic number" . The file -.B /etc/magic +.I /etc/magic specifies what magic numbers are to be tested for, what message to print if a particular magic number is found, and additional information to extract from the file. @@ -113,7 +116,7 @@ then presumably print that string, by doing .IP message The message to be printed if the comparison succeeds. If the string contains a -.IR printf (3S) +.BR printf (3S) format specification, the value from the file (with any specified masking performed) is printed using the message as the format string. .PP @@ -156,6 +159,15 @@ type specifier. To that number the value of .I y is added and the result is used as an offset in the file. The default type if one is not specified is long. +.PP +Sometimes you do not know the exact offset as this depends on the length of +preceding fields. You can specify an offset relative to the end of the +last uplevel field (of course this may only be done for sublevel tests, i.e. +test beginning with +.B > +). Such a relative offset is specified using +.B & +as a prefix to the offset. .SH BUGS The formats .IR long , @@ -176,7 +188,7 @@ a system on which the lengths are invariant. There is (currently) no support for specified-endian data to be used in indirect offsets. .SH SEE ALSO -.IR file (1) +.BR file (1) \- the command that reads this file. .\" .\" From: guy@sun.uucp (Guy Harris) @@ -191,4 +203,4 @@ indirect offsets. .\" the changes I posted to the S5R2 version. .\" .\" Modified for Ian Darwin's version of the file command. -.\" @(#)$Id$ +.\" @(#)$Id: magic.5,v 1.1.1.3 1997/03/18 17:58:57 mpp Exp $ |