man

Updated

September 4, 2026

Overview

man displays the system manual. Pages are organized into sections covering user commands, system calls, libraries, file formats, and admin tools. It remains the authoritative offline reference on Linux — faster and more version-accurate than random web snippets for the packages you actually have installed.

Most pages are viewed through a pager (usually less). Press q to quit, / to search.

Syntax

man [section] name
man [options] name
man -k keyword          # same as apropos
man -f name             # same as whatis

Sections (common)

Sec Content Example
1 User commands man 1 printf
2 System calls man 2 open
3 Library functions man 3 printf
4 Special files / devices man 4 null
5 File formats / configs man 5 passwd
6 Games —
7 Overviews / conventions man 7 signal
8 Admin commands man 8 mount
9 Kernel routines (some systems) —

When the same name exists in multiple sections (e.g. printf in 1 and 3, passwd in 1 and 5), specify the section number.

Common Options

Option Description
-k / --apropos Search short descriptions
-f / --whatis One-line summary for a known name
-a Show all matching sections in turn
-w / --path Print path to the man file, don’t open it
-W List all matching paths
-K Full-text search of page bodies (slow)
-P pager Override pager (less, cat, …)
-L locale Force locale for translated pages
MANPAGER / PAGER Environment override for pager
MANWIDTH Force formatting width (useful in scripts)

Examples with Explanations

Open a page

man ls
man 5 sshd_config
man 8 systemctl
man man

sshd_config lives in section 5 (file formats), not as a user command.

Disambiguate sections

man -a printf          # cycle through every section that has printf
man 3 printf           # C library specifically
whatis printf          # see which sections exist
man -w -a passwd       # paths for all passwd pages

Search when you forget the name

man -k resize
man -k 'disk usage'
apropos network interface
man -K 'AddressFamily'   # full-text; can take a while

Locate the source file

man -w ls
# e.g. /usr/share/man/man1/ls.1.gz
zcat "$(man -w ls)" | head

Useful when debugging missing or outdated pages after package installs.

Readable width and plain text dump

MANWIDTH=80 man ls
man ls | col -b > /tmp/ls.txt    # strip backspaces/overstrike
man -P cat ls | head -40

HTML / browser (if supported)

man -H ls                 # uses browser from $BROWSER or similar
man -Tutf8 ls | less -R

Scripting existence checks

if man -w journalctl >/dev/null 2>&1; then
  echo "journalctl man page present"
fi

Pager keys (less)

Key Action
q Quit
/pattern Search forward
?pattern Search backward
n / N Next / previous match
g / G Top / bottom
Space / b Page down / up
h Help

Notes / Pitfalls

  • Empty or stale results after installing packages: rebuild the index with sudo mandb (or sudo makewhatis on some BSDs / older systems).
  • Container images often ship without man pages to save space. Install man-db and the relevant *-doc / man packages, or read docs on the host.
  • Section order and default “first match” can surprise you — prefer explicit man 5 name for configs.
  • Locale: if a translated page is incomplete, force English with LANG=C man … or man -L C ….
  • man is not for shell builtins (cd, [[, declare) — use help (bash) instead.

2026-relevant notes

  • Systemd, iproute2, and Podman pages are high quality; prefer man systemctl, man ip-link, man podman-run over outdated blog posts for flag accuracy.
  • Many modern tools also ship --help that is good enough for flags; use man when you need semantics, exit codes, and file formats.
  • Container and snap sandboxes may not see host man pages; read docs in the environment where the tool is installed.

Additional Resources