Find Commands with apropos in Linux

What apropos does

apropos searches the names and short descriptions of all manual pages. Give it a word, and it lists the commands and pages that match.

Syntax

apropos [option] keyword

Examples

Find everything about networking:

apropos network

Search for two words, either one can match:

apropos -e "network|server"

Useful options

Ignore case with -i:

apropos -i email

Regular expression with -r (or -e for a pattern):

apropos -r "network|server"

Exact word with -w:

apropos -w network

One manual section with -s:

apropos -s 2 network

A real use

You need to make a backup but forget the command name:

apropos backup

You can also use apropos to learn: search for a topic and see which commands exist for it.

Limits

• apropos depends on the man-db package and its database. If you find nothing, update the database with sudo mandb.
• Results can include unrelated commands. Use -w or a pattern to narrow them.
• Large systems may answer a bit slowly.

Quick recap

• apropos keyword lists manual pages that match.
• Use -i, -w, -r and -s to filter.
• Run sudo mandb if the results are empty.