command comm compare two sorted files line by line

about comm

compare two sorted files line-by-line

syntax

comm [option]… file1 file2

description

compare sorted files file1 and file2

with no options, comm produces three-column output

• column 1 contains lines unique to file1
• column 2 contains lines unique to file2
• column 3 contains lines common to both files

each of these columns can be suppressed individually with options

options

• -1 suppress column 1 (lines unique to file1)
• -2 suppress column 2 (lines unique to file2)
• -3 suppress column 3 (lines that appear in both files)
• --check-order chech that the input is correctly sorted, even if all input lines are pairable
• --nocheck-order do not check that the input is correctly sorted
• --output-delimiter=str separate columns with string str
• --help display a help message and exit
• --version output version infomation and exit

examples

1. print only the lines present in both file1.txt and file2.txt

    comm -12 file1.txt file2.txt
   

2. print only the lines that are present in file1 and not in file2 and vice versa

    comm -3 file1.txt file2.txt
   

references

computerhope