5.2 System Documentation: man, info, and /usr/share/doc

RHCSA (EX200) is a performance exam. You will not browse arbitrary websites for answers, but you do have the system itself. Red Hat Enterprise Linux ships extensive local documentation: man pages, info manuals, short --help summaries, and files under /usr/share/doc. The official essential-tools objective expects you to locate, interpret, and use that documentation while solving tasks—especially when a flag, unit file field, or config syntax slips your mind.

Why Documentation Skills Are Graded Indirectly

Graders score the end state of the machine (service enabled, mode correct, network up). They do not score whether you memorized every tar option. Candidates who finish on time almost always open man mid-exam. Treating documentation as a first-class tool—not a last resort—reduces syntax errors and rework.

Typical uses:

• Confirm chmod symbolic grammar or find predicates
• Look up sshd_config keyword names (man section 5)
• Discover package example configs under /usr/share/doc
• Search which command relates to “logical volume” when the name escapes you

man: The Primary Manual Browser

Basic invocation

man ls
man chmod
man systemd.unit
man 5 passwd          # section 5: file format for passwd, not the passwd command
man 1 passwd          # section 1: the passwd user command

Inside man (less-based pager on RHEL):

Exam habit: Search inside the page for a keyword (/recursive, /example) instead of reading every line under time pressure.

Manual sections

Pages live in numbered sections. The same name can exist in more than one section with different content:

Examples that matter for admins:

man 1 crontab       # crontab command
man 5 crontab       # crontab file format
man 8 mount
man 5 fstab
man 7 systemd.directives

If you omit the section, man shows the first match according to a configured section search order (often user commands before formats). When the page feels “wrong” (command vs file format), specify the section explicitly.

Header lines look like CHMOD(1) or PASSWD(5)—the number is the section. That teaches you what kind of page you are reading.

man -k and apropos: Find by keyword

When you remember the task but not the binary name:

man -k password
apropos password
man -k 'logical volume'
man -k fstab

man -k / apropos search short descriptions in the whatis database. Results list names with sections, for example passwd (1), passwd (5). Then open the right page.

If keyword search returns nothing unexpected, the database may need rebuild after heavy package installs (historically mandb); on a standard exam image it should already be populated. Still, prefer exact man command when you know the name—it is faster than scanning long apropos output.

Related tools

whatis chmod          # one-line description from the database
man -f chmod          # same idea as whatis on many systems
man -a printf         # show all matching sections sequentially
man -w ls             # path to the man page file on disk

whatis is excellent for a quick sanity check that you have the right command before diving into a long page.

--help and Short Usage

Most GNU/CLI tools support:

chmod --help
systemctl --help
ssh -h                # some use -h instead of --help

--help is shorter than man and often enough for flag spelling. For configuration file syntax and behavioral notes, man section 5 or packaged docs beat --help.

info: Navigable GNU Manuals

info displays Texinfo documentation used heavily by GNU projects (coreutils, bash, grep, and others). Some topics have richer hierarchical manuals in info than in a single man page.

info
info coreutils
info coreutils 'ls invocation'
info bash
info libc

Basic navigation (standalone info browser):

If info feels awkward, start with info coreutils and follow the menu to a specific utility. Many admins still prefer man for day-to-day flags; use info when man says “this is only a summary” or when you need tutorial-style chapters.

Note: Some packages install man pages only; others emphasize info. Being able to open either without panic is the skill.

/usr/share/doc: Packaged Documentation Trees

Almost every RPM can drop files under:

/usr/share/doc/<package-name>-<version>/

or a simplified directory name depending on packaging. Typical contents:

• README, README.md, NEWS, TODO
• AUTHORS, COPYING / license texts
• example/ or examples/ sample configs
• HTML or text guides for complex services

Explore:

ls /usr/share/doc | less
ls /usr/share/doc | grep -i httpd
ls /usr/share/doc/openssh*
ls /usr/share/doc/coreutils*
find /usr/share/doc -iname '*example*' 2>/dev/null | head

On RHEL, package names match RPM names closely. After installing a package for an exam task, check whether /usr/share/doc includes sample configuration you can copy and adapt—faster and safer than inventing syntax from memory.

Also related:

rpm -qd package_name      # list documentation files owned by a package (when rpm is available)
rpm -ql package_name | grep /usr/share/doc

Software management chapters cover RPM deeply; here, know that docs are files on disk you can less or cat offline.

Documentation Hierarchy for Exam Speed

Use this decision order under time pressure:

1. Command you know, flag forgotten → command --help or man 1 command, search with /
2. Config file syntax → man 5 filename or man service.conf style pages; then check examples in /usr/share/doc
3. Forgot the command name → man -k keyword / apropos
4. Deep GNU tool behavior → info topic menus
5. Package-specific samples → /usr/share/doc/<pkg>/

Avoid endless scrolling. Extract the option, write the command, test, then re-check the system state.

Interpreting What You Read

Man pages use conventional notation:

• Bold or plain command names for literals to type
• Italic or angle brackets for replaceable arguments
• [optional] square brackets for optional syntax
• ... for repeated elements
• | for alternatives

Synopsis lines are dense—read them slowly once, then jump to EXAMPLES (many pages have that section) or search for a known option name.

Admin pitfalls:

• Copying an example meant for a different distribution path
• Using a section 1 command synopsis when you needed section 5 file format
• Applying an optional flag that changes destructive defaults without reading the description

Offline Reality of EX200

Expect no general internet for looking up blogs or external cheat sheets. The installed image’s man pages, info files, and /usr/share/doc are the allowed reference library. Help systems that require online connectivity are not a plan. Practice in a network-restricted lab: complete tasks while using only local docs.

Also available on systems:

help type          # bash builtin help (shell builtins)
help [[
compgen -c | less  # not docs, but discovery of command names

Bash builtins (cd, type, read, job control) often document better via help builtin than via external man pages—though many also have man pages.

Practical Scenario: “Configure X; syntax forgotten”

Task: restrict SSH and you forget the exact sshd_config keyword.

man 5 sshd_config
# inside pager: /PasswordAuthentication
# or: /PermitRootLogin
sudo vim /etc/ssh/sshd_config
sudo sshd -t && sudo systemctl reload sshd

Task: need find to locate setuid files—flag spelling uncertain.

man find
# /perm
# or: man -k setuid
find / -perm -4000 2>/dev/null

Task: package installed, need example unit or config.

ls /usr/share/doc | grep -i nginx
less /usr/share/doc/nginx*/README*

Common Pitfalls

• Reading passwd(1) when you needed passwd(5) field definitions
• Quitting without noticing you were in info vs man (different keys)—remember q exits both in normal setups
• Ignoring EXAMPLES sections that show the exact pattern you need
• Wasting time on web habits that do not exist on the exam network
• Forgetting documentation packages: minimal installs might omit some docs; exam environments are usually doc-friendly, but man missing for a topic means the package providing that page is not installed

RHEL 10 Notes

RHEL continues the standard Linux documentation layout: man-db tooling, less as pager, Texinfo/info for GNU manuals, and RPM-owned trees under /usr/share/doc. systemd-related topics often use multi-part man pages (systemd.unit, systemd.service, systemctl). When man systemctl is not enough, open the specific unit-type page named in SEE ALSO.

Section Checkpoint

You should open man and navigate with search, force the correct section, use man -k to rediscover tools, open info when a GNU manual is the better source, list and read /usr/share/doc for packaged examples, and fall back to --help for quick flags. On EX200, documentation fluency is time management: the system already contains the reference material—practice retrieving it without hesitation.