5.3.2. Filtering output

The command sort arranges lines in alphabetical order by default:

thomas:~> cat people-I-like | sort
Auntie Emmy
Boyfriend
Dad
Grandma
Mum
My boss

But there are many more things sort can do. Looking at the file size, for instance. With this command, directory content is sorted smallest files first, biggest files last:

ls -la | sort -nk 5

	Old sort syntax
	You might obtain the same result with ls -la | sort +4n, but this is an old form which does not comply with the current standards.

The sort command is also used in combination with the uniq program (or sort -u) to sort output and filter out double entries:

thomas:~> cat itemlist
1
4
2
5
34
567
432
567
34
555

thomas:~> sort itemlist | uniq
1
2
34
4
432
5
555
567