The cut command is a Unix/Linux tool used to literally cut text from files and output from other commands. With the cut command a user can take text and output only certain parts of the line.

In my opinion cut is the most under recognized and utilized command in Linux/Unix. This is mostly due to the fact that when most Sysadmins want to cut text from files or standard output many will reach for AWK.

While AWK is a great tool for quick and dirty commands; I tend to reach for cut before AWK. The below cheat sheet should show many ways to use cut with every day tasks.

Common Separated Values

Print the first field out of a CSV file

$ cut -d: -f1 passwd.bak 
  root
  daemon

Print the first field out of CSV output from another command

$ head -1 /etc/passwd | cut -d: -f1 
  root

Print the first, second, and seventh field out of a CSV file

To change the field simply change the numbers after -f separated by a comma.

$ cut -d: -f1,2,7 passwd.bak 
 root:x:/bin/bash

Print text based on Spaces

$ cut -d\  -f3 /etc/motd 
 Ubuntu

Print the fourth field and everything after that from a command

This command is pretty handy if you wanted to make a script out of the past few commands you ran.

$ history | cut -d\  -f 4- 
 ping google.com

Print up to the 4th field

$ cut -d\  -f-4 /etc/motd 
 Welcome to Ubuntu 12.04

Print all fields between 5 and 8

$ cut -d: -f5-8 passwd 
 root:/root:/bin/bash

 Output with a different delimiter (make a CSV)

Convert : to ,

$ cut --output-delimiter=, -d: -f1- passwd 
 root,x,0,0,root,/root,/bin/bash

Convert space to ,

$ ps -elf | cut --output-delimiter=, -d\ -f1-
F,S,UID,,,,,,,,PID,,PPID,,C,PRI,,NI,ADDR,SZ,WCHAN,,STIME,TTY,,,,,,,,,,TIME,CMD
4,S,root,,,,,,,,,1,,,,,0,,0,,80,,,0,-,,6083,poll_s,19:07,?,,,,,,,,00:00:12,/sbin/init

Output only lines that have a delimiter

This command will only output lines that have a : (in our example), within the file tmpfile there are multiple lines some with : and some without.

$ head tmpfile
Welcome to Ubuntu 12.04 LTS (GNU/Linux 3.2.0-29-generic x86_64)

73 packages can be updated.
10 updates are security updates.

root:x:0:0:root:/root:/bin/bash
daemon:x:1:1:daemon:/usr/sbin:/bin/sh
bin:x:2:2:bin:/bin:/bin/sh
sys:x:3:3:sys:/dev:/bin/sh
sync:x:4:65534:sync:/bin:/bin/sync

$ cut -s -d: -f1-4 tmpfile
root:x:0:0
daemon:x:1:1
bin:x:2:2
sys:x:3:3
sync:x:4:65534

 Bytes

Print bytes 1 through 45

$ cut -b1-45 /etc/motd
Welcome to Ubuntu 12.04 LTS (GNU/Linux 3.2.0-

Print everything but bytes 10 through 45

$ cut --complement -b10-45 /etc/motd
Welcome t29-generic x86_64)

Characters

Print characters 1 through 25

$ cut -c1-25 /etc/motd
Welcome to Ubuntu 12.04 L

Print everything but characters 10 through 25

$ cut --complement -c10-25 /etc/motd
Welcome tTS (GNU/Linux 3.2.0-29-generic x86_64)