📚 Linux/Unix: Manuals & Help Commands – man, info, and --help Explained

🧲 Introduction – Why Learn Linux Help Tools?

When you’re working in Linux, documentation is always at your fingertips—right from the terminal. Whether you’re trying to understand a command’s options, troubleshoot syntax, or explore advanced usage, tools like man, info, and --help offer instant guidance without needing to search online.

🎯 In this guide, you’ll learn:

• How to use man to read command manuals
• How to explore extended documentation with info
• How to quickly check options using --help
• Best practices for learning new commands efficiently

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📖 1. man – The Manual Pages

✅ What is man?

man (short for manual) displays the built-in documentation for nearly every command, configuration file, and library on a Unix/Linux system.

🛠️ Syntax:

man [command]

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🧪 Example:

man ls

📤 Output:
Displays the manual page for ls, including:

• Name and description
• Syntax and options
• Exit statuses
• Examples and notes

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🔍 Navigation Keys:

Key	Action
Space	Scroll forward
b	Scroll back
q	Quit manual page
/pattern	Search for a pattern
n/N	Repeat search forward/back

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🔹 Manual Sections:

Linux manuals are divided into numbered sections:

Section	Description
1	User commands (e.g., ls, cat)
5	File formats and config files
8	System administration commands

To view a specific section:

man 5 passwd

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📘 2. info – The GNU Info System

✅ What is info?

info provides more detailed, hyperlinked manuals, often richer than man. It’s mostly used for GNU utilities.

🛠️ Syntax:

info [command]

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🧪 Example:

info coreutils 'ls invocation'

📤 Output:
Shows a navigable menu structure with sections like Options, Usage, Examples, etc.

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🔍 Info Navigation Keys:

Key	Action
n	Next section
p	Previous section
u	Move up one level
Space	Scroll forward
q	Quit
m	Return to the main menu

🧠 info is useful for in-depth exploration when man is too brief.

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🧾 3. --help – Quick Command Reference

✅ What is --help?

The --help option is supported by most commands and gives a quick summary of available flags and usage—great for a fast lookup.

🛠️ Syntax:

command --help

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🧪 Examples:

ls --help

📤 Output (truncated):

Usage: ls [OPTION]... [FILE]...
List information about the FILEs (the current directory by default).
...
  -a, --all             do not ignore entries starting with .
  -l                    use a long listing format

🧠 Ideal for quick refreshers or script writers who don’t need full manuals.

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🧠 Tool Comparison Table

Tool	Purpose	Depth	Interactivity	Best Use Case
man	Full command manual	Medium	Scroll/search	Standard usage reference
info	Hypertext GNU documentation	High	Menu-based	Detailed, structured exploration
--help	Quick command-line summary	Low	Scroll only	Fast option reference

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📌 Summary – Recap & Next Steps

Linux makes it easy to learn as you go. With man, info, and --help, you can understand commands, debug errors, and optimize scripts without leaving the terminal.

🔍 Key Takeaways:

• Use man for standard command references and syntax.
• Use info for GNU command deep-dives with navigable menus.
• Use --help for quick flag lookups or reminders.

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❓ FAQs

❓ How do I find which manual sections are available for a command?
✅ Use:

man -f command

or

whatis command

❓ What if the man page is missing?
✅ Install the manual packages:

sudo apt install man-db

❓ How do I search for a command’s man page by keyword?
✅ Use:

man -k keyword

Example:

man -k network

❓ What’s the difference between man and info?
✅ man is brief and linear. info is detailed, with hyperlinks and menus.

❓ How do I see all options of a command without reading the manual?
✅ Use:

command --help

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