8.9 Viewing Text Files
When searching for the contents of a file with grep
the output gives you the line in which the searchstring
was found along with the filename. Often this contextual information is
still not enough information to decide whether you want to open and edit
this file. Bash offers you several commands to have a quick look at the
contents of a text file directly in the shell, without opening an
With head you can view the first lines of a text
file. If you do not specify the command any further,
head shows the first 10 lines of a text file.
The tail command is the counterpart of
head. If you use tail without any
further options it displays the last 10 lines of a text file. This can
be very useful to view log files of your system, where the most recent
messages or log entries are usually found at the end of the file.
With less, display the whole contents of a text
file. To move up and down half a page use PgUp
and PgDn. Use Space to
scroll down one page. Home takes you to the
beginning, and End to the end of the document. To
end the viewing mode, press Q.
Instead of less, you can also use the older
program more. It has basically the same
function—however, it is less convenient because it does not allow
you to scroll backwards. Use Space to move forward.
When you reach the end of the document, the viewer closes
The cat command displays the contents of a file,
printing the entire contents to the screen without interruption. As
cat does not allow you to scroll it is not very
useful as viewer but it is rather often used in combination with other