How to Use the 'man' Command (with Examples)

The man command is a powerful utility available in Unix and Unix-like operating systems that allows users to access and read manual pages (man pages) for commands and programs installed on the system. These manual pages provide detailed documentation, including a description of the functionality, usage options, and examples of how to use the command. The man command is an invaluable tool for both beginners and advanced users alike, offering insights and a deeper understanding of various system commands and their functionalities.

Use Case 1: Display the Man Page for a Command

Code:

man ls

Motivation: When you’re unsure about how to use a specific command or want to explore its options and functionalities, displaying its man page provides comprehensive information. For instance, if you’re new to the ls command or want to refresh your memory about its advanced options, using the man command will efficiently fulfill this need.

Explanation: man ls consists of two parts:

• man: The base command used to access and display the manual pages.
• ls: The command for which you want to view the manual. The man command will fetch and display the man page specifically for the ls command.

Example Output:

LS(1)                     GNU Coreutils                     LS(1)

NAME
       ls - list directory contents

SYNOPSIS
       ls [OPTION]... [FILE]...

DESCRIPTION
       List  information about the FILEs (the current directory by
       default).  Sort entries alphabetically if none of -cftuvSUX
       nor --sort is specified.
...

Use Case 2: Open the Man Page for a Command in a Browser

Code:

BROWSER=firefox man --html ls

Motivation: Sometimes, viewing the man page in a terminal might seem cumbersome due to limited screen real estate. If you prefer browsing through the documentation more comfortably in a web browser with additional capabilities such as easy navigation and search, opening the man page in a browser is a suitable alternative.

Explanation:

• BROWSER=firefox: This environment variable sets Firefox as the browser to open the man page. Ensure that the browser you specify is installed on your system.
• man --html: The --html option tells the man command to format the man page into HTML for better readability in a web browser.
• ls: This specifies that you want the man page for the ls command.

Example Output: Opening a web browser displaying the ls command’s man page in an HTML format.

Use Case 3: Display the Man Page for a Command from Section 7

Code:

man 7 signal

Motivation: Man pages are categorized into sections that organize the documentation based on types like user commands, system calls, games, file formats, etc. Sometimes there might be a conflict between command names across sections. If you need a system-specific interface or protocol, such as the specifications for certain signal types in section 7, this becomes crucial.

Explanation:

• man 7 signal:
  • man: The primary command to access manual pages.
  • 7: The specific section of the manual pages to search within.
  • signal: The subject of interest, in this case, man page information under section 7 related to signals.

Example Output:

SIGNAL(7)                Linux Programmer's Manual                SIGNAL(7)

NAME
       signal - overview of signals

DESCRIPTION
        Signals are a limited form of inter-process communication...

...

Use Case 4: List All Available Sections for a Command

Code:

man --whatis printf

Motivation: A single term, like printf, might be found in multiple sections of the manual. If you’re unsure about which section contains the relevant information for your context, listing all available sections helps confidently narrow down your search.

Explanation:

• man --whatis printf:
  • --whatis: This flag lists short descriptions related to all the commands or topics matching the query.
  • printf: The specific term you are querying about.

Example Output:

printf (1) - format and print data
printf (3) - formatted output conversion

Use Case 5: Display the Path Searched for Manpages

Code:

man --path

Motivation: Understanding where the system searches for man pages can be beneficial for troubleshooting issues or configuring additional repositories for custom or third-party manual entries.

Explanation:

• man --path: This simple command involves the --path option to reveal the directories explored during a man page search. No additional arguments are needed and the spool of paths gets recorded at this juncture.

Example Output:

/usr/share/man:/usr/local/share/man:/usr/local/man:/usr/man

Use Case 6: Display the Location of a Manpage Rather than the Manpage Itself

Code:

man --where ls

Motivation: If you want to learn where a man page file is stored within the filesystem—perhaps to view it using another file viewer or to edit it—a direct command to locate the man page file path becomes essential.

Explanation:

• man --where ls:
  • --where: Instead of displaying the manual content, the command returns the path to the man page file.
  • ls: The command name for which you’re locating the man page.

Example Output:

/usr/share/man/man1/ls.1.gz

Use Case 7: Display the Man Page Using a Specific Locale

Code:

man --locale=fr ls

Motivation: With localization support, users whose native language isn’t English or anyone needing documentation in a different language can more easily comprehend the contents of man pages. It’s crucial in multicultural environments or international collaborations.

Explanation:

• man --locale=fr ls:
  • --locale=fr: Requests the man page in French by specifying the locale option with the language code.
  • ls: Your target command retains the same integrity across languages but elucidated by region-specific documentation.

Example Output: Translated man page output will be presented, assuming the French version is installed.

Use Case 8: Search for Manpages Containing a Search String

Code:

man --apropos "proxy"

Motivation: When you have a concept or keyword but lack the exact command name, searching for man pages using a descriptive search string can illuminate associated commands or functionalities, providing better navigation through extensive documentation.

Explanation:

• man --apropos "proxy":
  • --apropos: This option searches through all the man pages for matching terms related to your query.
  • "proxy": The target search string for which results are desired.

Example Output:

proxy (1)             - connect to a proxy server
proxy-arp (8)         - make and delete proxy ARP entries
...

Conclusion

The man command forms the backbone of command-line proficiency in Unix-based systems. Through illustrative examples, we’ve explored its practical applications across various contexts, from displaying essential command documentation to resolving system-level inquiries and enhancing command-line efficiency. The versatility and comprehensiveness of man facilitate a deeper understanding of system operations, ensuring users can responsibly exploit and manipulate system utilities to their full extent.