.CD "comm \(en print lines common to two sorted files"
.SX "comm\fR [\fB\(en123\fR] \fIfile1 file2
.FL "\(en1" "Suppress column 1 (lines present only in \fIfile1\fP)" 
.FL "\(en2" "Suppress column 2 (lines present only in \fIfile2\fP)" 
.FL "\(en3" "Suppress column 3 (lines present in both files)"
.EX "comm file1 file2" "Print all three columns"
.EX "comm \(en12 file1 file2" "Print only lines common to both files"
.PP
Two sorted files are read and compared.
A three column listing is produced.
Files only in 
.I file1
are in column 1;
files only in
.I file2
are in column 2;
files common to both files are in column 3.
The file name \(en means \fIstdin\fR. 



.SP 1.5