head And tail

head

Documentation

• man -s 1 head

• By default, write first ten lines to stdout

  $ head /etc/passwd
  root:x:0:0:root:/root:/bin/bash
  bin:x:1:1:bin:/bin:/sbin/nologin
  daemon:x:2:2:daemon:/sbin:/sbin/nologin
  adm:x:3:4:adm:/var/adm:/sbin/nologin
  lp:x:4:7:lp:/var/spool/lpd:/sbin/nologin
  sync:x:5:0:sync:/sbin:/bin/sync
  shutdown:x:6:0:shutdown:/sbin:/sbin/shutdown
  halt:x:7:0:halt:/sbin:/sbin/halt
  mail:x:8:12:mail:/var/spool/mail:/sbin/nologin
  operator:x:11:0:operator:/root:/sbin/nologin
  

• First N lines: -n N, --lines N

  $ head -n 3 /etc/passwd
  root:x:0:0:root:/root:/bin/bash
  bin:x:1:1:bin:/bin:/sbin/nologin
  daemon:x:2:2:daemon:/sbin:/sbin/nologin
  

• All but the last N lines: -n -N (negative number)

  $ head -n -43 /etc/passwd
  root:x:0:0:root:/root:/bin/bash
  bin:x:1:1:bin:/bin:/sbin/nologin
  daemon:x:2:2:daemon:/sbin:/sbin/nologin
  adm:x:3:4:adm:/var/adm:/sbin/nologin
  

• First N bytes: -c N (also with negative N, as with -n)

  $ head -c 3 /etc/passwd
  roo$
  

tail

Documentation

• man -s 1 tail

• By default, write last ten lines to stdout

  $ tail /etc/passwd
  abrt:x:173:173::/etc/abrt:/sbin/nologin
  flatpak:x:986:983:User for flatpak system helper:/:/sbin/nologin
  gdm:x:42:42:GNOME Display Manager:/var/lib/gdm:/sbin/nologin
  gnome-initial-setup:x:985:982::/run/gnome-initial-setup/:/sbin/nologin
  vboxadd:x:984:1::/var/run/vboxadd:/sbin/nologin
  sshd:x:74:74:Privilege-separated SSH:/usr/share/empty.sshd:/sbin/nologin
  tcpdump:x:72:72::/:/sbin/nologin
  jfasch:x:1000:1000:Joerg Faschingbauer:/home/jfasch:/bin/bash
  systemd-coredump:x:978:978:systemd Core Dumper:/:/usr/sbin/nologin
  systemd-timesync:x:977:977:systemd Time Synchronization:/:/usr/sbin/nologin
  

• Write all but first N lines: -n +N, --lines +N

  $ tail -n +43 /etc/passwd
  sshd:x:74:74:Privilege-separated SSH:/usr/share/empty.sshd:/sbin/nologin
  tcpdump:x:72:72::/:/sbin/nologin
  jfasch:x:1000:1000:Joerg Faschingbauer:/home/jfasch:/bin/bash
  systemd-coredump:x:978:978:systemd Core Dumper:/:/usr/sbin/nologin
  systemd-timesync:x:977:977:systemd Time Synchronization:/:/usr/sbin/nologin
  

head And tail In The Pipe

• Lines 8-10 to stdout

  $ head -n 10 /etc/passwd|tail -n 3
  halt:x:7:0:halt:/sbin:/sbin/halt
  mail:x:8:12:mail:/var/spool/mail:/sbin/nologin
  operator:x:11:0:operator:/root:/sbin/nologin
  

  Or, less efficient (thereby winning the Useless Use Of Cat Award),

  $ cat /etc/passwd|head -n 10|tail -n 3
  halt:x:7:0:halt:/sbin:/sbin/halt
  mail:x:8:12:mail:/var/spool/mail:/sbin/nologin
  operator:x:11:0:operator:/root:/sbin/nologin