Getting help: man, info, --help
You open manual pages (man) and move around in them, learn what the sections mean and the different sections of the same name, search for unknown commands with man -k and apropos, use help for the shell’s own commands, info for long documents and --help for a quick look; at the end you answer the questions given to you from the documentation. The questions differ in every lab.
Level 101 · 40 min
No expert knows every command and option by heart. The difference is knowing where to look. Daniel puts it like this: "Before you search the internet, look at the machine’s own documentation; the server may have no internet, but the documents are always there."
Linux has three sources of help: man (manual) is each command’s official, detailed document; info is the longer, chaptered book of some GNU tools; --help is a command’s short usage summary. For the shell’s own commands (cd, pushd…) there is help.
Analogy: man is a car’s owner’s manual, --help the quick reference card in the glove box, info the service handbook.
What you will do in this lesson
- Your first manual page: man ls
- Sections: man 5 passwd
- Search for a command you don’t know: man -k, apropos
- Reading the SYNOPSIS
- The shell’s help: help
- The long document: info
- Quick identification: whatis
- Answer from the documentation
- Which section?
- Short quiz
Skills you will earn
- Reading and searching manual pages
- Using manual sections (man 5 passwd, whatis)
- Searching for an unknown command (man -k, apropos)
- Using help for the shell’s commands
- Reading info documents
- Reading a command’s help (--help)
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