comm – compare two sorted files line by line


$comm sorta.txt sortb.txt
d
g
comm: file 1 is not in sorted order
e
s

x
comm: file 2 is not in sorted order
g
s
n

$cat sorta.txt
d
g
e
s

$cat sortb.txt
x
g
s
n

$

$cat sorta.txt
a
b
c
d
$cat sortb.txt
a
f
g
h
$comm sorta.txt sortb.txt
a
b
c
d
f
g
h
$
comm - compare two sorted files line by line

With no options, produce three-column output.
Column one contains lines unique to FILE1, column
two contains lines unique to FILE2, and column three
contains lines common to both files.

Reference/Source :
Debian manual for command "comm".