Question

Is there a “canonical” way of doing that? I’ve been using head -n | tail -1 which does the trick, but I’ve been wondering if there’s a Bash tool that specifically extracts a line (or a range of lines) from a file.

By “canonical” I mean a program whose main function is doing that.

Answer 1

head and pipe with tail will be slow for a huge file. I would suggest sed like this:

sed 'NUMq;d' file

Where NUM is the number of the line you want to print; so, for example, sed '10q;d' file to print the 10th line of file.

Explanation:

NUMq will quit immediately when the line number is NUM.

d will delete the line instead of printing it; this is inhibited on the last line because the q causes the rest of the script to be skipped when quitting.

If you have NUM in a variable, you will want to use double quotes instead of single:

sed "${NUM}q;d" file