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This guide explains how to find and use on-system documentation in Red Hat Enterprise Linux (RHEL). Think of the machine’s built-in docs as your local server manual: you can look up commands, options, configuration formats, and examples without needing an Internet connection. Primary on-system documentation tools you will use frequently:
  • The manual pages: man <command>
  • A command’s short usage summary: <command> --help
  • The GNU info system: info <command>
Quick examples:
Man pages are the canonical local reference on RHEL. Use --help for quick usage summaries and info when a program provides more verbose, tutorial-style documentation.

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man pages: structure and navigation

Man pages (the man system) provide detailed reference material for commands, configuration files, system calls, libraries, and administration tools. Typical sections of a man page include:
  • NAME
  • SYNOPSIS
  • DESCRIPTION
  • OPTIONS
  • EXAMPLES
  • FILES
  • SEE ALSO
Common navigation keys (man uses the less pager by default):
  • Space — scroll down one page
  • Enter — scroll down one line
  • b or B — scroll up one page
  • /pattern — search forward for pattern
  • n — repeat search in same direction
  • N — repeat search in opposite direction
  • g — jump to top of page
  • G — jump to bottom of page
  • q — quit the man page
Man pages are organized into numbered sections. Use the section number to disambiguate entries with the same name. You can request a specific section; for example:

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Example: viewing the ls manual

To read the ls man page:
Inside you will find the NAME, SYNOPSIS (how to call it), and the DESCRIPTION with all options and explanations. Use the search and navigation keys above to find the option or example you need quickly — most people query a man page for a specific flag or usage pattern rather than reading it end-to-end. If you want a short, human-friendly summary of commonly used options:
For more structured, tutorial-like documentation (when available), try info:

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Searching the manual database

If you only know a keyword but not the exact command name, man -k (or apropos) searches the man short descriptions (the whatis database):
If man -k returns nothing useful, the manual index might be out of date. Rebuild the man database with mandb; this typically requires root privileges:
mandb must be run with appropriate privileges (usually via sudo or as root) to rebuild the system man database. Running it as an unprivileged user will not update the global index.
After rebuilding, search again:
Example (trimmed) output might include:
From this output you can choose which command matches your intent (for example, use useradd to create new users).

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Examples of section disambiguation

Some names appear in multiple man sections. Use the section number to pick the intended topic:

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Package-specific documentation: /usr/share/doc

Not all documentation lives in man pages. Many installed packages place additional files under /usr/share/doc. These directories often contain README files, FAQs, examples, and sometimes HTML documentation. List installed package documentation:
Inspect a specific package (example: Bash):
Files such as INTRO, README, and FAQ can provide background material, configuration examples, and troubleshooting hints that are not always present in man pages.

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Tips and best practices

  • Use man for authoritative, on-system references and exact option syntax.
  • Use --help for quick summaries and common options.
  • Use info for programs that offer more tutorial-style documentation.
  • Use man -k or apropos to find commands by keyword. If results look stale, run sudo mandb to rebuild the index.
  • Search inside man pages with /pattern and navigate between matches with n and N.
  • Look for an EXAMPLES section in complex man pages — practical examples are often the fastest way to learn how to use a command.
  • When scripting or automating, prefer reading the SYNOPSIS and OPTIONS sections to avoid unexpected behavior.

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Further reading and references

This article has shown how to locate, read, and use local system documentation on RHEL using man, --help, info, man -k/apropos, mandb, and files under /usr/share/doc. You do not need to memorize everything — learn how to find authoritative details quickly and apply them when you need them.

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