Finding tool help

Most command-line tools can show you how to use it when you execute it with argument -h or --help, for example:

cp --help

It is common for command-line tools to have a manual page that provides full documentation. The manual pages are split into 8 sections:

1. User commands / programs
2. System calls
3. Library calls
4. Special files
5. File formats and conventions
6. Games
7. Miscellaneous
8. System administration commands

They can be viewed with the man command. To view the manual page of a command-line tool you can simply type e.g. (for the cp command):

man cp

You can view the manual page from a specific section by inserting the section number in between. For example to get the manual page about the format of configuration file /etc/crontab you can use:

man 5 crontab

Without an explicit section number after the man command you will get the manual page with the lowest section number. (Actually man crontab also works fine, because there is no manual page with that name in a lower section.) For further information about the man command itself you can view its manual page with:

man man

These are comparable to manual pages. Use the info command to view them, for example:

info cp

Further information about how to use the info command can be found in:

info info

This is the default location for the documentation of installed software (incl. things like Python libraries). It often at least contains a simple README file and the change log (describing what was changed in each release).