freebsd-skq/usr.bin/comm/comm.1
tjr 2ec6e3b662 Document the fact that comm(1) does not recognize multibyte characters
in its input. Although doing so would require only trivial changes,
it would be incompatible with the ordering used by sort(1), which is the
primary source of comm's input.
2004-06-24 15:57:56 +00:00

110 lines
3.4 KiB
Groff

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.\" From: @(#)comm.1 8.1 (Berkeley) 6/6/93
.\" $FreeBSD$
.\"
.Dd June 25, 2004
.Os
.Dt COMM 1
.Sh NAME
.Nm comm
.Nd select or reject lines common to two files
.Sh SYNOPSIS
.Nm
.Op Fl 123i
.Ar file1 file2
.Sh DESCRIPTION
The
.Nm
utility reads
.Ar file1
and
.Ar file2 ,
which should be
sorted lexically, and produces three text
columns as output: lines only in
.Ar file1 ;
lines only in
.Ar file2 ;
and lines in both files.
.Pp
The filename ``-'' means the standard input.
.Pp
The following options are available:
.Bl -tag -width indent
.It Fl 1
Suppress printing of column 1.
.It Fl 2
Suppress printing of column 2.
.It Fl 3
Suppress printing of column 3.
.It Fl i
Case insensitive comparison of lines.
.El
.Pp
Each column will have a number of tab characters prepended to it
equal to the number of lower numbered columns that are being printed.
For example, if column number two is being suppressed, lines printed
in column number one will not have any tabs preceding them, and lines
printed in column number three will have one.
.Pp
The
.Nm
utility assumes that the files are lexically sorted; all characters
participate in line comparisons.
.Sh DIAGNOSTICS
.Ex -std
.Sh SEE ALSO
.Xr cmp 1 ,
.Xr diff 1 ,
.Xr sort 1 ,
.Xr uniq 1
.Sh STANDARDS
The
.Nm
utility conforms to
.St -p1003.2-92 .
.Sh HISTORY
A
.Nm
command appeared in
.At v4 .
.Sh BUGS
The
.Nm
utility does not recognize multibyte characters in order to remain
compatible with the current implementation of
.Xr sort 1 .