nl

Number lines from a file or from stdin. More information: https://manned.org/nl.1p.

• Number non-blank lines in a file:

nl {{path/to/file}}

• Read from stdin:

{{command}} | nl -

• Number [a]ll [b]ody lines including blank lines or do [n]ot number [b]ody lines:

nl -b {{a|n}} {{path/to/file}}

• Number only the [b]ody lines that match a basic regular expression (BRE) [p]attern:

nl -b p'FooBar[0-9]' {{path/to/file}}

• Use a specific [i]ncrement for line numbering:

nl -i {{increment}} {{path/to/file}}

• Specify the line numbering format to [r]ight or [l]eft justified, keeping leading [z]eros or [n]ot:

nl -n {{rz|ln|rn}}

• Specify the line numbering's [w]idth (6 by default):

nl -w {{col_width}} {{path/to/file}}

• Use a specific string to [s]eparate the line numbers from the lines (TAB by default):

nl -s {{separator}} {{path/to/file}}