Add numbers to the beginning of every line in a file

Question

How can I add numbers to the beginning of every line in a file?

E.g.:

This is
the text
from the file.

Becomes:

000000001 This is
000         


        

Answer 1

You're looking for the nl(1) command:

$ nl -nrz -w9  /etc/passwd
000000001   root:x:0:0:root:/root:/bin/bash
000000002   daemon:x:1:1:daemon:/usr/sbin:/bin/sh
000000003   bin:x:2:2:bin:/bin:/bin/sh
...

-w9 asks for numbers nine digits long; -nrz asks for the numbers to be formatted right-justified with zero padding.