tldr/pages/common/nl.md

nl

A utility for numbering lines, either from a file, or from stdin. More information: https://www.gnu.org/software/coreutils/nl.

• Number non-blank lines in a file:

nl {{path/to/file}}

• Read from stdout:

cat {{path/to/file}} | nl {{options}} -

• Number only the lines with printable text:

nl -t {{path/to/file}}

• Number all lines including blank lines:

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

• Number only the body lines that match a basic regular expression (BRE) pattern:

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