.TH COMM 1L "GNU Text Utilities" "FSF" \" -*- nroff -*-
.SH NAME
comm \- compare two sorted files line by line
.SH SYNOPSIS
.B comm
[\-123] [\-\-help] [\-\-version] file1 file2
.SH DESCRIPTION
This manual page
documents the GNU version of
.BR comm .
.B comm
prints lines that are common, and lines that are unique, to two input
files.  The two files must be sorted before
.B comm
can be used.  The file name `\-' means the standard input.
.PP
With no options,
.B comm
produces three column output.  Column
one contains lines unique to
.IR file1 ,
column two contains
lines unique to
.IR file2 ,
and column three contains lines common to both files.
.SS OPTIONS
.PP
The options
.IR \-1 ,
.IR \-2 ,
and
.I \-3
suppress printing of the corresponding columns.
.TP
.I "\-\-help"
Print a usage message and exit with a non-zero status.
.TP
.I "\-\-version"
Print version information on standard error then exit.