The default settings of the TAIL command is to output the last 10 lines of a file

tail /var/log messages

will output the last 10 lines of your /var/log/messages file

Mar 24 11:25:20 mirage dbus-daemon[1094]: dbus[1094]

Mar 24 11:25:20 mirage dbus[1094]: [system] Successfully activated service 'org.freedesktop

Mar 24 11:27:44 mirage dbus-daemon[1094]: dbus[1094]: [system] Activating service name

Mar 24 11:27:44 mirage dbus[1094]: [system] Activating service name='net.reactivated

Mar 24 11:27:44 mirage dbus-daemon[1094]: Launching FprintObject

Mar 24 11:27:44 mirage dbus[1094]: [system] Successfully activated service 'net.reactivated.Fprint'

Mar 24 11:27:44 mirage dbus-daemon[1094]: dbus[1094]: [system]

Mar 24 11:27:44 mirage dbus-daemon[1094]:

Mar 24 11:27:44 mirage dbus-daemon[1094]: ** Message: entering main loop

This alias changes the default setting of tail so that it outputs all the lines that can fit on your screen.

just add the following to your .bashrc if you use bash or your .zshrc if you use zsh as your terminal editor.

alias tail='tail -n $((${LINES:-`tput lines 2>/dev/null||echo -n 80`} - 7))'

then source youre .bashrc or .zshrc by typing

source .bashrc or

source .zshrc

or just restart your terminal

next time you run tail on a file you will get as many lines as will fill up your screen.