This commit was manufactured by cvs2svn to create tag 'FreeBSD-release/1.0'.

[unix-history] / usr.bin / file / magic.5

diff --git a/usr.bin/file/magic.5 b/usr.bin/file/magic.5
index d736dce..7479f27 100644 (file)
--- a/usr.bin/file/magic.5
+++ b/usr.bin/file/magic.5
@@ -1,13 +1,4 @@
-.\"
-.\" PATCHES MAGIC                LEVEL   PATCH THAT GOT US HERE
-.\" --------------------         -----   ----------------------
-.\" CURRENT PATCH LEVEL:         1       00103
-.\" --------------------         -----   ----------------------
-.\"
-.\" 16 Feb 93  Rodney W. Grimes        Fixed all the commands that had two
-.\"                                    dots in them.
-.\"
-.TH MAGIC FILES "Public Domain"
+.TH MAGIC 5 "Public Domain"

 .\" install as magic.4 on USG, magic.5 on V7 or Berkeley systems.
 .SH NAME
 magic \- file command's magic number file
 .\" install as magic.4 on USG, magic.5 on V7 or Berkeley systems.
 .SH NAME
 magic \- file command's magic number file


@@ -38,12 +29,33 @@ The type of the data to be tested.  The possible values are:
 .IP byte \w'message'u+2n
 A one-byte value.
 .IP short
 .IP byte \w'message'u+2n
 A one-byte value.
 .IP short

-A two-byte value (on most systems).
+A two-byte value (on most systems) in this machine's native byte order.

 .IP long
 .IP long

-A four-byte value (on most systems).
+A four-byte value (on most systems) in this machine's native byte order.

 .IP string
 A string of bytes.
 .IP string
 A string of bytes.

+.IP date
+A four-byte value interpreted as a unix date.
+.IP beshort
+A two-byte value (on most systems) in big-endian byte order.
+.IP belong
+A four-byte value (on most systems) in big-endian byte order.
+.IP bedate
+A four-byte value (on most systems) in big-endian byte order,
+interpreted as a unix date.
+.IP leshort
+A two-byte value (on most systems) in little-endian byte order.
+.IP lelong
+A four-byte value (on most systems) in little-endian byte order.
+.IP ledate
+A four-byte value (on most systems) in little-endian byte order,
+interpreted as a unix date.

 .RE
 .RE

+The numeric types may optionally be followed by
+.B &
+and a numeric value,
+to specify that the value is to be AND'ed with the
+numeric value before any comparisons are done.

 .IP test
 The value to be compared with the value from the file.  If the type is
 numeric, this value
 .IP test
 The value to be compared with the value from the file.  If the type is
 numeric, this value


@@ -61,10 +73,14 @@ value,
 .BR > ,
 to specify that the value from the file must be greater than the specified
 value,
 .BR > ,
 to specify that the value from the file must be greater than the specified
 value,

-or

 .BR & ,
 .BR & ,

-to specify that the value is to be AND'ed with the
-numeric value before any comparisons are done.
+to specify that the value from the file must have set all of the bits 
+that are set in the specified value,
+or
+.BR ^ ,
+to specify that the value from the file must have clear any of the bits 
+that are set in the specified value.
+.IP

 Numeric values are specified in C form; e.g.
 .B 13
 is decimal,
 Numeric values are specified in C form; e.g.
 .B 13
 is decimal,


@@ -78,9 +94,19 @@ is omitted, it is assumed to be
 .IP
 For string values, the byte string from the
 file must match the specified byte string. 
 .IP
 For string values, the byte string from the
 file must match the specified byte string. 

-The operators =, < and > (but not &) can be applied to strings.
+The operators
+.BR = ,
+.B <
+and
+.B >
+(but not
+.BR & )
+can be applied to strings.

 The length used for matching is that of the string argument
 The length used for matching is that of the string argument

-in the magic file.
+in the magic file.  This means that a line can match any string, and
+then presumably print that string, by doing
+.B >\e0
+(because all strings are greater than the null string).

 .IP message
 The message to be printed if the comparison succeeds.  If the string
 contains a
 .IP message
 The message to be printed if the comparison succeeds.  If the string
 contains a


@@ -91,30 +117,61 @@ performed) is printed using the message as the format string.
 Some file formats contain additional information which is to be printed
 along with the file type.  A line which begins with the character
 .B >
 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.  If the test on the
-line preceding the first line with a
+indicates additional tests and messages to be printed.  The number of

 .B >
 .B >

-succeeds, the tests specified in all the subsequent lines beginning with
+on the line indicates the level of the test; a line with no

 .B >
 .B >

+at the beginning is considered to be at level 0.
+Each line at level
+.IB n \(pl1
+is under the control of the line at level
+.IB n
+most closely preceding it in the magic file.
+If the test on a line at level
+.I 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
 are performed, and the messages printed if the tests succeed.  The next

-line which does not begin with a
-.B >
+line at level
+.I n

 terminates this.
 terminates this.

+If the first character following the last
+.B >
+is a
+.B (
+then the string after the parenthesis is interpreted as an indirect offset.
+That means that the number after the parenthesis is used as a 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 value of 
+.I 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
+if one is not specified is long.

 .SH BUGS
 The formats 
 .SH BUGS
 The formats 

-.I long
+.IR long ,
+.IR belong ,
+.IR lelong ,
+.IR short ,
+.IR beshort ,
+.IR leshort ,
+.IR date ,
+.IR bedate ,

 and
 and

-.I short
+.I ledate

 are system-dependant; 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
 are system-dependant; 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

-There should be more than one level of subtests,
-with the level possibly indicated by
-the number of
-.B >
-at the beginning of the line.
+There is (currently) no support for specified-endian data to be used in
+indirect offsets.

 .SH SEE ALSO
 .IR file (1)
 \- the command that reads this file.
 .SH SEE ALSO
 .IR file (1)
 \- the command that reads this file.


@@ -131,4 +188,4 @@ at the beginning of the line.
 .\" the changes I posted to the S5R2 version.
 .\"
 .\" Modified for Ian Darwin's version of the file command.
 .\" the changes I posted to the S5R2 version.
 .\"
 .\" Modified for Ian Darwin's version of the file command.

-.\" @(#)$Header: magic.4,v 1.5 87/11/06 20:54:31 ian Exp $
+.\" @(#)magic.5,v 1.3 1993/06/10 00:38:13 jtc Exp