head
head — first lines of a file. It is one of the commands you type in a terminal, and everything below is produced by running it: the output, the error you get when it goes wrong, and a terminal you can type it into yourself.
What it prints
Run against a small demo project — the same one you get in the terminal below, so the output is what you will see, not an illustration of it.
$ head -n 5 log.txtok start error: disk full ok done error: retry ok finished
What it looks like when it goes wrong
The most common mistake with head, and the exact message you get. Recognising the wording is most of the fix.
$ head -n 3 missing.txthead: missing.txt: No such file or directory
Common flags
- -nhow many lines
Other commands
Try it yourself
Same files as above. Nothing here can break, and nothing leaves your browser.
Where you use it
Lessons that have you type head on a real task, rather than read about it.
Written by Mikhail Kuzmitskii