Polecenia head i tail

Polecenie head wyświetla początkowe 10 wierszy pliku na ekranie.

Przykład:

[janek@localhost ~]$ sudo head /var/log/messages
Jun 23 15:39:59 localhost NetworkManager[655]: <warn> nl_recvmsgs() error: (-33) Dump inconsistency detected, interrupted
Jun 23 15:43:55 localhost clamd[1498]: SelfCheck: Database status OK.
Jun 23 15:51:30 localhost dbus-daemon[542]: dbus[542]: [system] Activating service name='net.reactivated.Fprint' (using servicehelper)
Jun 23 15:51:30 localhost dbus[542]: [system] Activating service name='net.reactivated.Fprint' (using servicehelper)
Jun 23 15:51:30 localhost dbus-daemon[542]: dbus[542]: [system] Successfully activated service 'net.reactivated.Fprint'
Jun 23 15:51:30 localhost dbus[542]: [system] Successfully activated service 'net.reactivated.Fprint'
Jun 23 15:51:30 localhost dbus-daemon[542]: Launching FprintObject
Jun 23 15:51:30 localhost dbus-daemon[542]: ** Message: D-Bus service launched with name: net.reactivated.Fprint
Jun 23 15:51:30 localhost dbus-daemon[542]: ** Message: entering main loop
Jun 23 15:51:34 localhost kernel: [ 5239.846923] EXT4-fs (sda7): mounted filesystem with ordered data mode. Opts: (null)

Polecenie to wypisuje pierwsze 10 wierszy pliku /var/log/messages.

Polecenie tail wypisuje 10 ostatnich wierszy pliku.na ekranie.

Przykład:

[janek@localhost ~]$ sudo tail /var/log/messages

Jun 24 21:58:12 localhost dbus-daemon[547]: Exiting

Jun 24 21:58:14 localhost dbus-daemon[547]: dbus[547]: [system] Activating service name='org.freedesktop.UDisks' (using servicehelper)

Jun 24 21:58:14 localhost dbus[547]: [system] Activating service name='org.freedesktop.UDisks' (using servicehelper)

Jun 24 21:58:14 localhost dbus-daemon[547]: dbus[547]: [system] Successfully activated service 'org.freedesktop.UDisks'

Jun 24 21:58:14 localhost dbus[547]: [system] Successfully activated service 'org.freedesktop.UDisks'

Jun 24 21:59:52 localhost clamd[1493]: SelfCheck: Database status OK.

Jun 24 22:01:42 localhost gnome-keyring-daemon[6435]: couldn't access conrol socket: /run/user/1000/keyring-dOX6bf/control: Nie ma takiego pliku ani katalogu

Jun 24 22:01:42 localhost gnome-keyring-daemon[6435]: couldn't set environment variable in session: The name org.gnome.SessionManager was not provided by any .service files

Jun 24 22:01:57 localhost gnome-keyring-daemon[6435]: couldn't allocate secure memory to keep passwords and or keys from being written to the disk

Jun 24 22:10:19 localhost clamd[1493]: SelfCheck: Database status OK.

Polecenie to wypisuje 10 ostatnich wierszy pliku /var/log/messages.