nl
$ nl [--body-numbering style] [--increment number] [--separator string] [--startnum number] [--width number] [file...]-b style, --body-numbering style: Line numbering style: 't' for non-empty lines, 'a' for all lines, 'n' for no lines-i number, --increment number: Line count increment-s string, --separator string: Separator between line numbers and lines-v number, --startnum number: Initial line number-w number, --width number: Number widthfile: Files to process