man — manual — is the reference book that ships inside every Linux system. It documents thousands of commands in a standard format, offline and free, and reading it well is the moment a terminal user stops needing a search engine for basics.
Open a page #
$ man ls
$ man 5 crontabThe pager opens with the command's synopsis, description, and every flag documented. Navigate with the keys:
| Key | Action |
|---|---|
| Space / b | Page down / up |
| arrows or j / k | One line at a time |
/pattern | Search forward, n for the next match |
g / G | Jump to top / bottom |
q | Quit |
The search key is the one that changes everything: open man grep, type /recurse, and you are reading exactly the paragraph you needed.
The sections #
Man pages live in numbered sections — 1 for user commands, 5 for file formats, 8 for administration. man 5 crontab documents the crontab file format, while man 1 crontab documents the command. When a name exists in several worlds, the section number picks the right one, and man -k lists every page mentioning a keyword:
$ man -k "copy files"
cp (1) - copy files and directoriesman vs --help #
--help is the author's one-screen summary; man is the full book. Use --help to remind yourself of a flag, man to actually learn the command. If a page feels endless, the SYNOPSIS at the top is a compressed grammar of every accepted form — worth reading slowly once per command.
Every command in this series — grep, find, tar — has a page worth ten minutes. The terminal notes series itself lives in the journal.