-.\" $OpenBSD: file.1,v 1.7 2000/03/04 22:19:23 aaron Exp $
-.TH FILE 1 "Copyrighted but distributable"
-.SH NAME
-file
-\- determine file type
-.SH SYNOPSIS
-.B file
-[
-.B \-vczL
-]
-[
-.B \-f
-namefile ]
-[
-.B \-m
-magicfiles ]
-file ...
-.SH DESCRIPTION
+.\" $OpenBSD: file.1,v 1.8 2000/03/06 02:38:19 aaron Exp $
+.\" $FreeBSD: src/usr.bin/file/file.1,v 1.16 2000/03/01 12:19:39 sheldonh Exp $
+.Dd July 30, 1997
+.Dt FILE 1
+.Os
+.Sh NAME
+.Nm file
+.Nd determine file type
+.Sh SYNOPSIS
+.Nm file
+.Op Fl vczL
+.Op Fl f Ar namefile
+.Op Fl m Ar magicfiles
+.Ar file Op Ar ...
+.Sh DESCRIPTION
This manual page documents version 3.22 of the
-.B file
+.Nm
command.
-.B File
+.Nm
tests each argument in an attempt to classify it.
There are three sets of tests, performed in this order:
filesystem tests, magic number tests, and language tests.
-The
-.I first
-test that succeeds causes the file type to be printed.
-.PP
+The first test that succeeds causes the file type to be printed.
+.Pp
The type printed will usually contain one of the words
-.B text
+.Dq text
(the file contains only
-.SM ASCII
+.Tn ASCII
characters and is probably safe to read on an
-.SM ASCII
+.Tn ASCII
terminal),
-.B executable
+.Dq executable
(the file contains the result of compiling a program
-in a form understandable to some \s-1UNIX\s0 kernel or another),
+in a form understandable to some
+.Ux
+kernel or another),
or
-.B data
-meaning anything else (data is usually `binary' or non-printable).
+.Dq data
+meaning anything else (data is usually binary or non-printable).
+.Pp
Exceptions are well-known file formats (core files, tar archives)
that are known to contain binary data.
When modifying the file
-.I /etc/magic
+.Pa /etc/magic
or the program itself,
-.B "preserve these keywords" .
+.Em "preserve these keywords" .
+.Pp
People depend on knowing that all the readable files in a directory
-have the word ``text'' printed.
-Don't do as Berkeley did \- change ``shell commands text''
-to ``shell script''.
-.PP
+have the word
+.Dq text
+printed.
+Don't do as Berkeley did; change
+.Dq shell commands text
+to
+.Dq shell script .
+.Pp
The filesystem tests are based on examining the return from a
-.BR stat (2)
+.Xr stat 2
system call.
The program checks to see if the file is empty,
or if it's some sort of special file.
implement them)
are intuited if they are defined in
the system header file
-.IR sys/stat.h .
-.PP
+.Aq Pa sys/stat.h .
+.Pp
The magic number tests are used to check for files with data in
particular fixed formats.
The canonical example of this is a binary executable (compiled program)
-.I a.out
+.Pa a.out
file, whose format is defined in
-.I a.out.h
+.Aq Pa a.out.h
and possibly
-.I exec.h
+.Aq Pa exec.h
in the standard include directory.
-These files have a `magic number' stored in a particular place
-near the beginning of the file that tells the \s-1UNIX\s0 operating system
+These files have a
+.Dq magic number
+stored in a particular place
+near the beginning of the file that tells the
+.Ux
+operating system
that the file is a binary executable, and which of several types thereof.
-The concept of `magic number' has been applied by extension to data files.
+.Pp
+The concept of magic number has been applied by extension to data files.
Any file with some invariant identifier at a small fixed
offset into the file can usually be described in this way.
The information in these files is read from the magic file
-.I /etc/magic.
-.PP
+.Pa /etc/magic .
+.Pp
If an argument appears to be an
-.SM ASCII
+.Tn ASCII
file,
-.B file
+.Nm
attempts to guess its language.
The language tests look for particular strings (cf
-.IR names.h )
+.Pa names.h )
that can appear anywhere in the first few blocks of a file.
For example, the keyword
-.B .br
+.Em .br
indicates that the file is most likely a
-.BR troff (1)
+.Xr troff 1
input file, just as the keyword
-.B struct
+.Li struct
indicates a C program.
These tests are less reliable than the previous
two groups, so they are performed last.
The language test routines also test for some miscellany
(such as
-.BR tar (1)
+.Xr tar 1
archives) and determine whether an unknown file should be
-labelled as `ascii text' or `data'.
-.SH OPTIONS
-.TP 8
-.B \-v
+labelled as
+.Dq ASCII text
+or
+.Dq data .
+.Pp
+The options are as follows:
+.Bl -tag -width indent
+.It Fl v
Print the version of the program and exit.
-.TP 8
-.B \-m list
-Specify an alternate list of files containing magic numbers.
+.It Fl m Ar list
+Specify an alternate
+.Ar list
+of files containing magic numbers.
This can be a single file, or a colon-separated list of files.
-.TP 8
-.B \-z
+.It Fl z
Try to look inside compressed files.
-.TP 8
-.B \-c
+.It Fl c
Cause a checking printout of the parsed form of the magic file.
This is usually used in conjunction with
-.B \-m
+.Fl m
to debug a new magic file before installing it.
-.TP 8
-.B \-f namefile
+.It Fl f Ar namefile
Read the names of the files to be examined from
-.I namefile
+.Ar namefile
(one per line)
before the argument list.
Either
-.I namefile
+.Ar namefile
or at least one filename argument must be present;
-to test the standard input, use ``-'' as a filename argument.
-.TP 8
-.B \-L
-option causes symlinks to be followed, as the like-named option in
-.BR ls (1).
+to test the standard input, use
+.Dq -
+as a filename argument.
+.It Fl L
+Cause symlinks to be followed, as the like-named option in
+.Xr ls 1 .
(on systems that support symbolic links).
-.SH FILES
-.I /etc/magic
-\- default list of magic numbers
-.SH ENVIRONMENT
-The environment variable
-.B MAGIC
-can be used to set the default magic number files.
-.SH SEE ALSO
-.BR magic (5)
-\- description of magic file format.
-.br
-.BR strings (1), " od" (1)
-\- tools for examining non-textfiles.
-.SH STANDARDS CONFORMANCE
+.El
+.Sh FILES
+.Bl -tag -width /etc/magic -compact
+.It Pa /etc/magic
+default list of magic numbers
+.El
+.Sh ENVIRONMENT
+The following environment varibles affect the execution of
+.Nm file :
+.Pp
+.Bl -tag -width indent
+.Ev MAGIC
+Default magic number files.
+.El
+.Sh SEE ALSO
+.Xr hexdump 1 ,
+.Xr od 1 ,
+.Xr strings 1 ,
+.Xr magic 5
+.Sh STANDARDS CONFORMANCE
This program is believed to exceed the System V Interface Definition
of FILE(CMD), as near as one can determine from the vague language
contained therein.
Its behaviour is mostly compatible with the System V program of the same name.
This version knows more magic, however, so it will produce
different (albeit more accurate) output in many cases.
-.PP
+.Pp
The one significant difference
between this version and System V
-is that this version treats any whitespace
+is that this version treats any white space
as a delimiter, so that spaces in pattern strings must be escaped.
For example,
-.br
->10 string language impress\ (imPRESS data)
-.br
+.Pp
+>10 string language impress\ (imPRESS data)
+.Pp
in an existing magic file would have to be changed to
-.br
->10 string language\e impress (imPRESS data)
-.br
+.Pp
+>10 string language\e impress (imPRESS data)
+.Pp
In addition, in this version, if a pattern string contains a backslash,
it must be escaped. For example
-.br
-0 string \ebegindata Andrew Toolkit document
-.br
+.Pp
+0 string \ebegindata Andrew Toolkit document
+.Pp
in an existing magic file would have to be changed to
-.br
-0 string \e\ebegindata Andrew Toolkit document
-.br
-.PP
+.Pp
+0 string \e\ebegindata Andrew Toolkit document
+.Pp
SunOS releases 3.2 and later from Sun Microsystems include a
-.BR file (1)
+.Xr file 1
command derived from the System V one, but with some extensions.
My version differs from Sun's only in minor ways.
-It includes the extension of the `&' operator, used as,
+It includes the extension of the
+.Ql &
+operator, used as,
for example,
-.br
->16 long&0x7fffffff >0 not stripped
-.SH MAGIC DIRECTORY
+.Pp
+>16 long&0x7fffffff >0 not stripped
+.Sh MAGIC DIRECTORY
The magic file entries have been collected from various sources,
mainly USENET, and contributed by various authors.
-Christos Zoulas (address below) will collect additional
+.An Christos Zoulas
+(address below) will collect additional
or corrected magic file entries.
A consolidation of magic file entries
will be distributed periodically.
-.PP
The order of entries in the magic file is significant.
Depending on what system you are using, the order that
they are put together may be incorrect.
If your old
-.B file
+.Nm
command uses a magic file,
keep the old magic file around for comparison purposes
(rename it to
-.IR /etc/magic.orig ).
-.SH HISTORY
+.Pa /etc/magic.orig ) .
+.Sh HISTORY
There has been a
-.B file
-command in every \s-1UNIX\s0 since at least Research Version 6
+.Nm
+command in every
+.Ux
+since at least Research Version 6
(man page dated January, 1975).
The System V version introduced one significant major change:
the external list of magic number types.
This slowed the program down slightly but made it a lot more flexible.
-.PP
+.Pp
This program, based on the System V version,
-was written by Ian Darwin without looking at anybody else's source code.
-.PP
-John Gilmore revised the code extensively, making it better than
+was written by
+.An Ian Darwin
+without looking at anybody else's source code.
+.Pp
+.An John Gilmore
+revised the code extensively, making it better than
the first version.
-Geoff Collyer found several inadequacies
+.An Geoff Collyer
+found several inadequacies
and provided some magic file entries.
The program has undergone continued evolution since.
-.SH AUTHOR
-Written by Ian F. Darwin, ian@darwinsys.com.
-.PP
-Altered by Rob McMahon, cudcv@warwick.ac.uk, 1989, to extend the `&' operator
-from simple `x&y != 0' to `x&y op z'.
-.PP
-Altered by Guy Harris, guy@auspex.com, 1993, to:
-.RS
-.PP
-put the ``old-style'' `&'
-operator back the way it was, because 1) Rob McMahon's change broke the
-previous style of usage, 2) the SunOS ``new-style'' `&' operator,
-which this version of
-.B file
-supports, also handles `x&y op z', and 3) Rob's change wasn't documented
-in any case;
-.PP
-put in multiple levels of `>';
-.PP
-put in ``beshort'', ``leshort'', etc. keywords to look at numbers in the
+.Sh AUTHORS
+Written by
+.An Ian F. Darwin Aq ian@sq.com ,
+UUCP address {utzoo | ihnp4}!darwin!ian,
+postal address: P.O. Box 603, Station F, Toronto, Ontario, CANADA M4Y 2L8.
+.Pp
+Altered by
+.An Rob McMahon Aq cudcv@warwick.ac.uk ,
+1989, to extend the
+.Ql &
+operator from simple
+.Dq x&y != 0
+to
+.Dq x&y op z .
+.Pp
+Altered by
+.An Guy Harris Aq guy@auspex.com ,
+1993, to:
+.Bl -item -offset indent
+.It
+put the
+.Dq old-style
+.Ql &
+operator back the way it was, because
+.Bl -enum -offset indent
+.It
+Rob McMahon's change broke the
+previous style of usage,
+.It
+The SunOS
+.Dq new-style
+.Ql &
+operator, which this version of
+.Nm
+supports, also handles
+.Dq x&y op z ,
+.It
+Rob's change wasn't documented in any case;
+.El
+.It
+put in multiple levels of
+.Ql > ;
+.It
+put in
+.Dq beshort ,
+.Dq leshort ,
+etc. keywords to look at numbers in the
file in a specific byte order, rather than in the native byte order of
the process running
-.BR file .
-.RE
-.PP
-Changes by Ian Darwin and various authors including
-Christos Zoulas (christos@deshaw.com), 1990-1997.
-.SH LEGAL NOTICE
-This program is distributed under the terms of the accompanying
-license file LEGAL.NOTICE.
-.PP
-A few support files (\fIgetopt\fP, \fIstrtok\fP)
+.Nm file .
+.El
+.Pp
+Changes by
+.An Ian Darwin
+and various authors including
+.An Christos Zoulas Aq christos@deshaw.com ,
+1990-1992.
+.Sh LEGAL NOTICE
+Copyright (c) Ian F. Darwin, Toronto, Canada,
+1986, 1987, 1988, 1989, 1990, 1991, 1992, 1993.
+.Pp
+This software is not subject to and may not be made subject to any
+license of the American Telephone and Telegraph Company, Sun
+Microsystems Inc., Digital Equipment Inc., Lotus Development Inc., the
+Regents of the University of California, The X Consortium or MIT, or
+The Free Software Foundation.
+.Pp
+This software is not subject to any export provision of the United States
+Department of Commerce, and may be exported to any country or planet.
+.Pp
+Permission is granted to anyone to use this software for any purpose on
+any computer system, and to alter it and redistribute it freely, subject
+to the following restrictions:
+.Bl -enum -offset indent
+.It
+The author is not responsible for the consequences of use of this
+software, no matter how awful, even if they arise from flaws in it;
+.It
+The origin of this software must not be misrepresented, either by
+explicit claim or by omission. Since few users ever read sources,
+credits must appear in the documentation;
+.It
+Altered versions must be plainly marked as such, and must not be
+misrepresented as being the original software. Since few users
+ever read sources, credits must appear in the documentation;
+.It
+This notice may not be removed or altered.
+.El
+.Pp
+A few support files
+.Pf ( Fn getopt ,
+.Fn strtok )
distributed with this package
-are by Henry Spencer and are subject to the same terms as above.
-.PP
-A few simple support files (\fIstrtol\fP, \fIstrchr\fP)
+are by
+.An Henry Spencer
+and are subject to the same terms as above.
+.Pp
+A few simple support files
+.Pf ( Fn strtol ,
+.Fn strchr )
distributed with this package
are in the public domain; they are so marked.
-.PP
+.Pp
The files
-.I tar.h
+.Pa tar.h
and
-.I is_tar.c
-were written by John Gilmore from his public-domain
-.B tar
+.Pa is_tar.c
+were written by
+.An John Gilmore
+from his public-domain
+.Nm tar
program, and are not covered by the above restrictions.
-.SH BUGS
+.Sh BUGS
There must be a better way to automate the construction of the Magic
-file from all the glop in Magdir. What is it?
+file from all the glop in Magdir.
+What is it?
Better yet, the magic file should be compiled into binary (say,
-.BR ndbm (3)
+.Xr ndbm 3
or, better yet, fixed-length
-.SM ASCII
+.Tn ASCII
strings for use in heterogenous network environments) for faster startup.
Then the program would run as fast as the Version 7 program of the same name,
with the flexibility of the System V version.
-.PP
-.B File
+.Pp
+.Nm
uses several algorithms that favor speed over accuracy,
thus it can be misled about the contents of
-.SM ASCII
+.Tn ASCII
files.
-.PP
+.Pp
The support for
-.SM ASCII
+.Tn ASCII
files (primarily for programming languages)
is simplistic, inefficient and requires recompilation to update.
-.PP
-There should be an ``else'' clause to follow a series of continuation lines.
-.PP
+.Pp
+There should be an
+.Dq else
+clause to follow a series of continuation lines.
+.Pp
The magic file and keywords should have regular expression support.
Their use of
-.SM "ASCII TAB"
+.Tn ASCII TAB
as a field delimiter is ugly and makes
it hard to edit the files, but is entrenched.
-.PP
+.Pp
It might be advisable to allow upper-case letters in keywords
for e.g.,
-.BR troff (1)
+.Xr troff 1
commands vs man page macros.
Regular expression support would make this easy.
-.PP
+.Pp
The program doesn't grok \s-2FORTRAN\s0.
It should be able to figure \s-2FORTRAN\s0 by seeing some keywords which
appear indented at the start of line.
Regular expression support would make this easy.
-.PP
+.Pp
The list of keywords in
-.I ascmagic
+.Em ascmagic
probably belongs in the Magic file.
-This could be done by using some keyword like `*' for the offset value.
-.PP
-Another optimisation would be to sort
+This could be done by using some keyword like
+.Ql *
+for the offset value.
+.Pp
+Another optimization would be to sort
the magic file so that we can just run down all the
tests for the first byte, first word, first long, etc, once we
have fetched it. Complain about conflicts in the magic file entries.
Make a rule that the magic entries sort based on file offset rather
than position within the magic file?
-.PP
+.Pp
The program should provide a way to give an estimate
-of ``how good'' a guess is.
-We end up removing guesses (e.g. ``From '' as first 5 chars of file) because
-they are not as good as other guesses (e.g. ``Newsgroups:'' versus
-"Return-Path:"). Still, if the others don't pan out, it should be
+of
+.Dq how good
+a guess is.
+We end up removing guesses (e.g.,
+.Dq From\
+as first 5 chars of file) because
+they are not as good as other guesses (e.g.,
+.Dq Newsgroups:
+versus
+.Qq Return-Path: ) .
+Still, if the others don't pan out, it should be
possible to use the first guess.
-.PP
-This program is slower than some vendors' file commands.
-.PP
+.Pp
+This program is slower than some vendors'
+.Nm
+commands.
+.Pp
This manual page, and particularly this section, is too long.
-.SH AVAILABILITY
+.Sh AVAILABILITY
You can obtain the original author's latest version by anonymous FTP
-at
-.I ftp://ftp.astron.com/pub/file/
-with a name like
-.I file-X.YY.tar.gz .
+on
+.Em ftp.deshaw.com
+in the directory
+.Pa /pub/file/file-X.YY.tar.gz
+
-.\" $OpenBSD: magic.5,v 1.3 1997/02/09 23:58:28 millert Exp $
+.\" $OpenBSD: magic.5,v 1.4 2000/03/06 02:38:19 aaron Exp $
+.\"
+.\" @(#)$FreeBSD: src/usr.bin/file/magic.5,v 1.11 2000/03/01 12:19:39 sheldonh Exp $
+.\"
.\" install as magic.4 on USG, magic.5 on V7 or Berkeley systems.
-.TH MAGIC 5 "Public Domain"
-.SH NAME
-magic \- file command's magic number file
-.SH DESCRIPTION
+.\"
+.Dd September 3, 1994
+.Dt MAGIC 5
+.Os
+.Sh NAME
+.Nm magic
+.Nd file command's magic number file
+.Sh DESCRIPTION
This manual page documents the format of the magic file as
used by the
-.BR file (1)
+.Xr file 1
command, version 3.22. The
-.B file
+.Nm 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" .
+.Dq magic number .
+.Pp
The file
-.I /etc/magic
+.Pa /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.
-.PP
+.Pp
Each line of the file specifies a test to be performed.
A test compares the data starting at a particular offset
in the file with a 1-byte, 2-byte, or 4-byte numeric value or
-a string. If the test succeeds, a message is printed.
+a string.
+If the test succeeds, a message is printed.
The line consists of the following fields:
-.IP offset \w'message'u+2n
+.Bl -tag -width indent
+.It Sy offset
A number specifying the offset, in bytes, into the file of the data
which is to be tested.
-.IP type
-The type of the data to be tested. The possible values are:
-.RS
-.IP byte \w'message'u+2n
+.It Sy type
+The type of the data to be tested.
+The possible values are:
+.Bl -tag -width beshort
+.It Sy byte
A one-byte value.
-.IP short
+.It Sy short
A two-byte value (on most systems) in this machine's native byte order.
-.IP long
+.It Sy long
A four-byte value (on most systems) in this machine's native byte order.
-.IP string
+.It Sy string
A string of bytes.
-.IP date
-A four-byte value interpreted as a unix date.
-.IP beshort
+.It Sy date
+A four-byte value interpreted as a
+.Ux
+date.
+.It Sy beshort
A two-byte value (on most systems) in big-endian byte order.
-.IP belong
+.It Sy belong
A four-byte value (on most systems) in big-endian byte order.
-.IP bedate
+.It Sy bedate
A four-byte value (on most systems) in big-endian byte order,
-interpreted as a unix date.
-.IP leshort
+interpreted as a
+.Ux
+date.
+.It Sy leshort
A two-byte value (on most systems) in little-endian byte order.
-.IP lelong
+.It Sy lelong
A four-byte value (on most systems) in little-endian byte order.
-.IP ledate
+.It Sy ledate
A four-byte value (on most systems) in little-endian byte order,
-interpreted as a unix date.
-.RE
-.PP
+interpreted as a
+.Ux
+date.
+.El
+.El
+.Pp
The numeric types may optionally be followed by
-.B &
+.Ql &
and a numeric value,
to specify that the value is to be AND'ed with the
-numeric value before any comparisons are done. Prepending a
-.B u
+numeric value before any comparisons are done.
+Prepending a
+.Sq u
to the type indicates that ordered comparisons should be unsigned.
-.IP test
-The value to be compared with the value from the file. If the type is
+.Bl -tag -width indent
+.It Sy test
+The value to be compared with the value from the file.
+If the type is
numeric, this value
is specified in C form; if it is a string, it is specified as a C string
-with the usual escapes permitted (e.g. \en for new-line).
-.IP
+with the usual escapes permitted (e.g.,
+.Ql \en
+for newline).
+.It Sy ""
Numeric values
may be preceded by a character indicating the operation to be performed.
It may be
-.BR = ,
+.Ql =
to specify that the value from the file must equal the specified value,
-.BR < ,
+.Ql <
to specify that the value from the file must be less than the specified
value,
-.BR > ,
+.Ql >
to specify that the value from the file must be greater than the specified
value,
-.BR & ,
+.Ql &
to specify that the value from the file must have set all of the bits
that are set in the specified value,
-.BR ^ ,
+.Ql ^
to specify that the value from the file must have clear any of the bits
that are set in the specified value, or
-.BR x ,
-to specify that any value will match. If the character is omitted,
+.Sq x
+to specify that any value will match.
+If the character is omitted,
it is assumed to be
-.BR = .
-.IP
-Numeric values are specified in C form; e.g.
-.B 13
+.Ql = .
+.It Sy ""
+Numeric values are specified in C form; e.g.,
+.Dq 13
is decimal,
-.B 013
+.Dq 013
is octal, and
-.B 0x13
+.Dq 0x13
is hexadecimal.
-.IP
+.It Sy ""
For string values, the byte string from the
file must match the specified byte string.
The operators
-.BR = ,
-.B <
+.Ql = ,
+.Ql < ,
and
-.B >
+.Ql >
(but not
-.BR & )
+.Ql & )
can be applied to strings.
The length used for matching is that of the string argument
-in the magic file. This means that a line can match any string, and
+in the magic file.
+This means that a line can match any string, and
then presumably print that string, by doing
-.B >\e0
+.Ql >\e0
(because all strings are greater than the null string).
-.IP message
-The message to be printed if the comparison succeeds. If the string
+.It Sy message
+The message to be printed if the comparison succeeds.
+If the string
contains a
-.BR printf (3S)
+.Xr printf 3
format specification, the value from the file (with any specified masking
performed) is printed using the message as the format string.
-.PP
+.El
+.Pp
Some file formats contain additional information which is to be printed
-along with the file type. A line which begins with the character
-.B >
-indicates additional tests and messages to be printed. The number of
-.B >
+along with the file type.
+A line which begins with the character
+.Ql >
+indicates additional tests and messages to be printed.
+The number of
+.Ql >
on the line indicates the level of the test; a line with no
-.B >
+.Ql >
at the beginning is considered to be at level 0.
+.Pp
Each line at level
-.IB n \(pl1
+.Em n+1
is under the control of the line at level
-.IB n
+.Em n
most closely preceding it in the magic file.
If the test on a line at level
-.I n
+.Em n
succeeds, the tests specified in all the subsequent lines at level
-.IB n \(pl1
-are performed, and the messages printed if the tests succeed. The next
+.Em n+1
+are performed, and the messages printed if the tests succeed.
+The next
line at level
-.I n
+.Em n
terminates this.
+.Pp
If the first character following the last
-.B >
+.Ql >
is a
-.B (
+.Ql (
then the string after the parenthesis is interpreted as an indirect offset.
That means that the number after the parenthesis is used as an offset in
-the file. The value at that offset is read, and is used again as an offset
-in the file. Indirect offsets are of the form:
-.BI (( x [.[bsl]][+-][ y ]).
+the file.
+The value at that offset is read, and is used again as an offset
+in the file.
+.Pp
+Indirect offsets are of the form:
+.Dq (x[.[bsl]][+-][y]) .
The value of
-.I x
-is used as an offset in the file. A byte, short or long is read at that offset
+.Sq x
+is used as an offset in the file.
+A byte, short or long is read at that offset
depending on the
-.B [bsl]
-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
+.Dq [bsl]
+type specifier.
+To that number the value of
+.Sq 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
+.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.
+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 &
+.Ql > ) .
+Such a relative offset is specified using
+.Ql &
as a prefix to the offset.
-.SH BUGS
+.Sh BUGS
The formats
-.IR long ,
-.IR belong ,
-.IR lelong ,
-.IR short ,
-.IR beshort ,
-.IR leshort ,
-.IR date ,
-.IR bedate ,
+.Li long ,
+.Li belong ,
+.Li lelong ,
+.Li short ,
+.Li beshort ,
+.Li leshort ,
+.Li date ,
+.Li bedate ,
and
-.I ledate
+.Li ledate
are system-dependent; perhaps they should be specified as a number
of bytes (2B, 4B, etc),
since the files being recognized typically come from
a system on which the lengths are invariant.
-.PP
+.Pp
There is (currently) no support for specified-endian data to be used in
indirect offsets.
-.SH SEE ALSO
-.BR file (1)
-\- the command that reads this file.
+.Sh FILES
+.Bl -tag -width /etc/magic
+.It Pa /etc/magic
+.El
+.Sh SEE ALSO
+.Xr file 1
.\"
.\" From: guy@sun.uucp (Guy Harris)
.\" Newsgroups: net.bugs.usg
projects / openbsd / commitdiff