Locate, Read, and Use
System Documentation

Locate, read, and use system documentation including man, info, and files in /usr/share/doc

CIS126RH | RHEL System Administration 1
Mesa Community College

The RHCSA exam is an open-documentation exam — you are allowed to use local system documentation. This module covers the three primary documentation sources built into every RHEL system: man pages (the standard reference for commands, files, and system calls), info pages (detailed hyperlinked documentation for GNU tools), and /usr/share/doc (package-specific documentation, configuration examples, and README files). Knowing how to find and navigate all three sources efficiently is both a core skill and an exam advantage.

Learning Objectives

Read man pages efficiently — Open man pages, navigate sections, search within pages, and find man pages for commands, files, and system calls using section numbers
Search for documentation with apropos and whatis — Use apropos to find man pages by keyword and whatis to identify what a command does
Use info pages for GNU tool documentation — Navigate info pages with keyboard shortcuts and understand when info provides more detail than man
Find and use documentation in /usr/share/doc — Locate package documentation, configuration examples, and README files that help configure services

Man Pages: The Standard Reference

Man pages (manual pages) are the primary documentation for Linux commands, system calls, configuration files, and library functions.

# Open the man page for a command
$ man ls
$ man passwd
$ man systemctl

# Open a man page for a configuration file
$ man sshd_config
$ man sudoers
$ man fstab

# Navigate inside man (pager controls — uses less)
# SPACE or f   = next page
# b            = previous page
# /PATTERN     = search forward
# n            = next search match
# N            = previous search match
# G            = jump to end
# g            = jump to beginning
# q            = quit

Man pages are available during the RHCSA exam

The exam is an open-documentation exam. Use man COMMAND to check any flag, option, or syntax you are unsure of. On the exam, opening a man page is faster and more reliable than guessing.

Man Page Sections

Man pages are organised into numbered sections. When a topic appears in multiple sections, specifying the section number opens the correct page.

Section	Content	Example
1	User commands (executable programs)	`man 1 passwd` — the passwd command
2	System calls (kernel interfaces)	`man 2 open` — the open() system call
3	Library functions (C library)	`man 3 printf` — the printf() function
4	Special files (devices in /dev)	`man 4 tty` — the tty device
5	File formats and conventions	`man 5 passwd` — the /etc/passwd format
6	Games and screensavers	(rarely used)
7	Miscellaneous (standards, conventions)	`man 7 signal` — signal overview
8	System administration commands	`man 8 sshd` — the sshd daemon

# passwd appears in section 1 (command) AND section 5 (file format)
$ man 1 passwd    # the passwd command
$ man 5 passwd    # the /etc/passwd file format

Navigating and Searching Man Pages

# Search for a keyword within the open man page
# After opening man sshd_config, find PasswordAuthentication:
# Type:  /PasswordAuthentication  then press ENTER
# Press: n  for the next match
# Press: N  for the previous match

# Open man page showing a specific section (SYNOPSIS, OPTIONS, etc.)
$ man --pager 'less +/EXAMPLES' crontab
# Opens man crontab and jumps to the first match of "EXAMPLES"

# Display the man page as plain text (no pager)
$ man ls | cat

# Grep inside a man page
$ man useradd | grep -A2 '\-u'
       -u, --uid UID
           The numerical value of the user's ID. This value must be unique,
           unless the -o option is used. ...

# Find which man page to read for a configuration directive
$ man 5 sshd_config   # format of /etc/ssh/sshd_config
$ man 5 sudoers        # format of /etc/sudoers
$ man 5 crontab        # format of a crontab file
$ man 5 fstab          # format of /etc/fstab

Finding Man Pages: apropos and whatis

apropos searches man page summaries by keyword. whatis shows the one-line description for a specific command.

# Search for man pages related to a keyword
$ apropos partition
cfdisk (8)       - display or manipulate a disk partition table
fdisk (8)        - manipulate disk partition table
gdisk (8)        - Interactive GUID partition table (GPT) manipulator
parted (8)       - a partition manipulation program
sfdisk (8)       - display or manipulate a disk partition table

# apropos is equivalent to: man -k
$ man -k partition   # same as apropos partition

# Find man pages related to user management
$ apropos user | grep "(8)"
groupadd (8)   - create a new group
passwd (1)     - update user's authentication tokens
useradd (8)    - create a new user or update default new user information
userdel (8)    - delete a user account and related files
usermod (8)    - modify a user account

# whatis: show the one-line description of a command
$ whatis chmod
chmod (1)  - change file mode bits

$ whatis passwd
passwd (1)  - update user's authentication tokens
passwd (5)  - password file
# whatis reveals that passwd exists in sections 1 AND 5

man -f and man -k: Built-in Search

# man -f is equivalent to whatis
$ man -f passwd
passwd (1)  - update user's authentication tokens
passwd (5)  - password file

# man -k is equivalent to apropos
$ man -k firewall
firewall-cmd (1) - firewalld command line client
firewall-config (1) - firewalld GUI configuration tool
firewalld (1)    - Dynamic Firewall Manager

# If apropos returns "nothing appropriate" — rebuild the database
$ sudo mandb
Processing manual pages under /usr/share/man...
Updating index cache for path /usr/share/man/man1 ...
...

# Find man pages using a regex pattern
$ man -k '^ssh'
ssh (1)         - OpenSSH remote login client
ssh-add (1)     - adds private key identities to the ssh-agent
ssh-agent (1)   - OpenSSH authentication agent
ssh-copy-id (1) - use locally available keys to authorise logins
ssh-keygen (1)  - OpenSSH authentication key utility
sshd (8)        - OpenSSH daemon

Use man -k when you cannot remember the exact command name

On the exam, man -k KEYWORD finds commands you know exist but cannot name exactly. man -k cron shows all cron-related commands; man -k logical volume shows LVM tools.

Info Pages: GNU Documentation

info pages are the primary documentation format for GNU tools. They provide more detail than man pages, with hyperlinked navigation between topics.

# Open the info page for a command
$ info coreutils       # GNU core utilities overview
$ info bash            # Bash reference manual
$ info ls              # info page for ls (part of coreutils)
$ info grep            # detailed grep documentation

# Navigate inside info
# SPACE or PageDown  = next screen
# DEL or PageUp      = previous screen
# n                  = next node (topic)
# p                  = previous node
# u                  = up to parent node
# ENTER on a link    = follow the link
# TAB                = move to next link in current node
# /PATTERN ENTER     = search forward
# q                  = quit

# If no info page exists, info falls back to the man page
$ info passwd          # shows man page if no info page

Info Navigation Cheat Sheet

Key	Action	Notes
`SPACE` / `PageDown`	Scroll down one screen	Same as less pager
`DEL` / `PageUp`	Scroll up one screen	Same as less pager
`n`	Next node at same level	Move to the next topic sibling
`p`	Previous node at same level	Move to the previous topic sibling
`u`	Up to parent node	Go back up the topic tree
`l`	Last (go back) — like browser back	Return to previously viewed node
`ENTER` on link	Follow the hyperlink	Links appear as `text`
`TAB`	Jump to next link in current node	Cycle through hyperlinks
`m`	Menu — go to a menu item by name	Type part of a node name
`/PATTERN`	Search forward for pattern	Works like / in less
`q`	Quit info	Return to shell

/usr/share/doc: Package Documentation

Every installed package deposits its documentation in /usr/share/doc/. This includes README files, configuration examples, changelog logs, and sometimes complete configuration templates.

# List the documentation directory for a package
$ ls /usr/share/doc/
bash  bind-utils  chrony  curl  dnf  httpd  openssl  rsync  vim-common ...

# View documentation for a specific package
$ ls /usr/share/doc/httpd/
CHANGES  LICENSE  NOTICE  README  VERSIONING

$ ls /usr/share/doc/rsync/
COPYING  INSTALL  NEWS  README.md  rsyncd.conf.5  support  tech_report.tex

# Many packages include example configuration files
$ ls /usr/share/doc/chrony/
COPYING  FAQ  NEWS  chrony.conf.example

# View the example config file
$ cat /usr/share/doc/chrony/chrony.conf.example

# Find which package provides documentation in /usr/share/doc
$ ls -la /usr/share/doc/ | grep vsftpd

Searching /usr/share/doc

# Find which package a directory belongs to
$ rpm -qd rsync
/usr/share/doc/rsync/COPYING
/usr/share/doc/rsync/NEWS
/usr/share/doc/rsync/README.md
/usr/share/man/man1/rsync.1.gz
/usr/share/man/man5/rsyncd.conf.5.gz

# rpm -qd lists ALL documentation files for a package
# including man pages, /usr/share/doc, and other doc files

# Search for example config files across all packages
$ find /usr/share/doc -name "*.conf*" -o -name "*.example*"
/usr/share/doc/chrony/chrony.conf.example
/usr/share/doc/vsftpd/EXAMPLE

# Search for README files
$ find /usr/share/doc -name "README*" -ls

# View compressed documentation
$ zcat /usr/share/doc/rsync/changelog.Debian.gz
$ zless /path/to/compressed.gz

rpm -qd PACKAGENAME lists all documentation for that package

When you know the package name but not where its documentation is, rpm -qd PACKAGENAME lists every documentation file — man pages, /usr/share/doc files, and any other doc files installed by that package.

Command-Line Help: --help

Most commands provide quick usage information with --help or -h — faster than a man page for a quick flag reminder.

# Show usage and options for a command
$ useradd --help
Usage: useradd [options] LOGIN
       useradd -D
       useradd -D [options]

Options:
  -b, --base-dir BASE_DIR  base directory for the home directory of the new
                             account
  -c, --comment COMMENT    GECOS field of the new account
  -d, --home-dir HOME_DIR  home directory of the new account
  -e, --expiredate EXPIRE_DATE  expiration date of the new account
  -f, --inactive INACTIVE  password inactivity period of the new account
  -g, --gid GROUP          name or ID of the primary group of the new account
  -G, --groups GROUPS      list of supplementary groups of the new account
  ...

# --help is faster than man for quick flag lookup
$ tar --help | grep "\-z"
  -z, --gzip, --gunzip, --ungzip   filter the archive through gzip

Documentation Sources: When to Use Each

Source	Best for	Access
`man COMMAND`	Complete reference for flags, options, and syntax of any command or configuration file	Always available; use `man 5` for config file formats
`man -k KEYWORD` / `apropos`	Finding the command name when you know what task you need to do	Requires `mandb` to be current
`COMMAND --help`	Quick flag reminder without reading a full page	Always available; no pager
`info COMMAND`	Detailed documentation for GNU tools — bash, grep, sed, awk, coreutils	Available for most GNU tools; falls back to man if not present
`/usr/share/doc/PACKAGE/`	Example config files, README files, and service-specific guides	Available for any installed package; use `ls` to browse
`rpm -qd PACKAGE`	Finding all documentation files for a specific installed package	Always available for any installed package

Documentation Quick Reference

Task	Command
Open man page for a command	`man COMMAND`
Open section 5 (file format) man page	`man 5 CONFIG_FILE`
Search within an open man page	Type `/PATTERN` then `n`
Find man pages by keyword	`apropos KEYWORD` or `man -k KEYWORD`
Show one-line description of a command	`whatis COMMAND` or `man -f COMMAND`
Rebuild the man page database	`sudo mandb`
Open info page for a command	`info COMMAND`
Quick help summary	`COMMAND --help`
List package documentation directory	`ls /usr/share/doc/PACKAGE/`
List all doc files for a package	`rpm -qd PACKAGE`
Find example config files	`find /usr/share/doc -name ".conf"`
View compressed documentation	`zless FILE.gz` or `zcat FILE.gz`

Common Mistakes

Mistake	What goes wrong	Correct approach
Not using man pages during the exam	Wrong flags or syntax — task fails due to a detail that could have been looked up	Use `man COMMAND` freely — the exam is open-documentation for local sources
Reading the wrong man page section	`man passwd` opens section 1 (command); section 5 (file format) is needed	Use `man 5 passwd` for file format; `whatis passwd` reveals all sections
Not knowing how to search within a man page	Scrolling through long man pages manually — wastes exam time	Type `/KEYWORD` inside the pager and press `n` to jump to matches
Ignoring /usr/share/doc for service configuration	Spending time parsing dense man pages when a clear example file exists	Check `ls /usr/share/doc/PACKAGENAME/` first — example configs save time
Getting "nothing appropriate" from apropos	The man page database is stale — search fails	Run `sudo mandb` to rebuild the database, then retry
Not using `COMMAND --help` for quick option lookup	Opening a full man page to find one flag — slower than necessary	`useradd --help \| grep gid` is faster than reading man useradd for the -g flag

Exam Documentation Strategy

The RHCSA exam allows use of local documentation. A systematic strategy saves time and prevents errors.

For any task involving a command you are unsure about

# 1. Quick options check
$ COMMAND --help | grep OPTION

# 2. Full syntax reference
$ man COMMAND           # then type /KEYWORD to jump

For any task involving a configuration file

# 1. Check for example files
$ ls /usr/share/doc/PACKAGENAME/

# 2. Configuration file format reference
$ man 5 CONFIGFILENAME    # e.g., man 5 sshd_config

# 3. Search within man page
# /DIRECTIVE_NAME then n to find the specific option

For a task when you cannot remember the command name

$ man -k KEYWORD         # find candidate commands
$ whatis CANDIDATE       # confirm it is the right one
$ man CANDIDATE          # read the full page

Knowledge Check

Answer these before moving to the next slide.

Write the command to find all man pages that mention the word "partition" in their description.
Write the command to open the man page for the /etc/passwd file format (not the passwd command). How do you know which section to use?
Inside an open man page, how do you search for the text "PasswordAuthentication"? How do you jump to the next match?
Write the command to list all documentation files installed by the httpd package, including man pages.
Where would you look for an example configuration file for the chrony package?
Write the three commands that form a systematic approach when you need to configure a service but cannot remember the exact directive name.

Knowledge Check — Answers

apropos partition or equivalently man -k partition — both search the man page database for "partition" in page names and summaries.
man 5 passwd — the format of the /etc/passwd file is documented in section 5 (file formats). Run whatis passwd first to confirm it shows both sections: passwd (1) (the command) and passwd (5) (the file format). Then use man 5 passwd to open the file format page.
Inside the open man page, type /PasswordAuthentication and press Enter. The pager jumps to the first match. Press n to jump to the next match. Press N to go back to the previous match.
rpm -qd httpd — lists all documentation files installed by the httpd package, including entries under /usr/share/doc/httpd/ and man pages under /usr/share/man/.
Check ls /usr/share/doc/chrony/ — this directory contains the chrony.conf.example file, which is a commented example configuration showing common settings.
(1) ls /usr/share/doc/PACKAGENAME/ to find example configuration files.
(2) man 5 CONFIGFILENAME to read the file format reference.
(3) Inside the man page, type /DIRECTIVE_NAME and press n to jump directly to the documentation for that specific directive.

Key Takeaways

The RHCSA exam allows local documentation — use it freely. Man pages, info pages, and /usr/share/doc are all available. A student who uses documentation to verify syntax will outperform one who relies on memory. Know how to navigate efficiently with /SEARCH and n.
Man pages cover commands (section 1), file formats (section 5), and daemons (section 8). man 5 sshd_config, man 5 sudoers, man 5 crontab, and man 5 fstab document exact configuration syntax. Use whatis TOPIC to discover which sections are available.
Use apropos/man -k when you cannot remember the command name. man -k partition, man -k logical volume, man -k firewall find the right tools. Rebuild the database with sudo mandb if searches return nothing.
Check /usr/share/doc/PACKAGE/ for configuration examples. Example config files are often more practical than man pages for service setup. rpm -qd PACKAGE lists all documentation files for any installed package. COMMAND --help | grep OPTION is the fastest option lookup.

Graded Lab

Run man ls. Navigate with SPACE and b. Search for "-l" by typing /-l inside the page and press n to find multiple matches. Practice pressing q to quit. Confirm you can find the meaning of the -Z flag.
Run whatis passwd to see both section 1 and section 5. Open each: man 1 passwd (the command), then man 5 passwd (the file format). In the section 5 page, search for the word "shell" to find the description of the shell field.
Use apropos cron to find documentation related to cron. Identify the man page for the crontab file format (section 5). Open it and search for the string "minute" to find the minute field specification.
Run info coreutils to open the GNU coreutils info page. Navigate using the menu to find the documentation for the ls command. Use u to go back to the top. Press q to quit.
Run ls /usr/share/doc/ and pick three installed packages. For each, list their documentation files. For any package that has an example config file, view it with cat or less.
Run rpm -qd bash and rpm -qd openssh-server to list all documentation files for those packages. Identify the man page for sshd_config from the output and open it. Search for "PermitRootLogin" to find the directive.

RHCSA Objective

"Locate, read, and use system documentation." Use man COMMAND and man 5 CONFIGFILE on the exam — search with /KEYWORD. Check /usr/share/doc/PACKAGE/ for examples. Use man -k KEYWORD to find commands you cannot name.

Next: Configure Access to RPM Repositories

Locate, Read, and UseSystem Documentation