By default, the
sort command will sort things alphabetically. If you have
numerical input though, you may want a numerical sort. This is what the
flag is for.
If I have a directory of files with numbered names, sort doesn’t quite do the job by itself.
$ ls | sort 1.txt 10.txt 11.txt 12.txt 2.txt 3.txt 4.txt 5.txt
-n flag, I get the sort order I am looking for.
$ ls | sort -n 1.txt 2.txt 3.txt 4.txt 5.txt 10.txt 11.txt 12.txt