When you first start using the shell, it can be intimidating. All you see is a prompt.
How do you know which commands are available, which options they use, or how to use advanced features?
Fortunately, lots of help is available. Here are some places you can look to supplement what you learn in this chapter:
- Check the PATH.Type echo $PATH. You see a list of the directories containing commands that are immediately accessible to you. Listing the contents of those directories displays most standard Linux commands.
- Use the help command.Some commands are built into the shell, so they do not appear in a directory.
The help command lists those commands and shows options available with each of them. (Type help | less to page through the list.) For help with a particular built-in command, type help command, replacing command with the name that interests you.
The help command works with the bash shell only.
with the command.
Many commands include a --help option that you can use to get information about how the command is used.
For example, type date --help | less. The output shows not only options, but also time formats you can use with the date command
- Use the man command. To learn more about a particular command, type man command. (Replace command with the command name you want.) A description of the command and its options appears on the screen.