How to View a File's Contents Without Opening It on Linux
With cat, less, head and tail, and when to use each one.
Short files: cat
cat file.txt
Dumps the entire content straight into the terminal — handy for short files, awkward for long files that don't fit on one screen.
Long files: less
less file.txt
Lets you navigate page by page with the arrow keys, search text
with /word, and quit with q — without
dumping everything onto the screen at once.
Just the beginning or the end
head file.txt # first 10 lines
tail file.txt # last 10 lines
tail -f file.log # follows the file live, useful for active logs
Tip: tail -f is especially useful for
watching a log file while something is running — it shows new lines
as they get written, without having to reopen the file each time.
Frequently asked questions
Which should I use for a very long file?
less, since it lets you navigate comfortably without dumping the entire content onto the screen at once the way cat does.
What exactly is tail -f for?
It shows in real time the new lines being added to a file, very useful for watching log files of something that's actively running.