$cat workethics.txt
Work
ethics
in
QA
Fashion
$nl workethics.txt > newfile
$cat new
new newfile
$cat newfile
1 Work
2 ethics
3 in
4 QA
5 Fashion
$
nl - number lines of files
Write each FILE to standard output, with line numbers added.
With no FILE, or when FILE is -, read standard input.
Reference/Source :
Debian Manual for "nl" command.
Beautiful Work 