What is the apropos command in Linux

By Thomas Taylor | | 1 minutes
Linux

Recently, I was made aware of the apropos command in Linux. What is it? What is it used for?

What is the apropos command?

apropos enables users to search terminal commands based on a keywords or descriptions.

This is an incredibly useful tool because it quickly identifies commands based on man pages.

Scenario: I forgot the command name for the qalculate CLI I installed.

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% apropos calculator
qalc(1)                  - Powerful and easy to use command line calculator
transicc(1)              - little cms ColorSpace conversion calculator
bc(1)                    - arbitrary-precision decimal arithmetic language and calculator
dc(1)                    - arbitrary-precision decimal reverse-Polish notation calculator
bc(1)                    - arbitrary-precision decimal arithmetic language and calculator
dc(1)                    - arbitrary-precision decimal reverse-Polish notation calculator

qalc was the first result.

Nothing appropriate error

If the man database is not updated, apropos may report an error when looking up commands:

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% apropos calculator
calculator: nothing appropriate.

To fix it, update the man pages:

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mandb