📚 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
manto read command manuals - How to explore extended documentation with
info - How to quickly check options using
--help - Best practices for learning new commands efficiently
📖 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]
🧪 Example:
man ls
📤 Output:
Displays the manual page for ls, including:
- Name and description
- Syntax and options
- Exit statuses
- Examples and notes
🔍 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 |
🔹 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
📘 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]
🧪 Example:
info coreutils 'ls invocation'
📤 Output:
Shows a navigable menu structure with sections like Options, Usage, Examples, etc.
🔍 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.
🧾 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
🧪 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.
🧠 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 |
📌 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
manfor standard command references and syntax. - Use
infofor GNU command deep-dives with navigable menus. - Use
--helpfor quick flag lookups or reminders.
❓ 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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