apropos Command Cheat Sheet
apropos searches the manual page names and descriptions for keywords. It's invaluable when you know what you want to do but don't know the exact command name. Essentially, it's a search engine for Linux commands.
Synopsis
apropos [OPTIONS] keyword ...
Description
apropos searches the whatis database (built from manual page descriptions) and displays short descriptions of system commands that match the keyword. It's equivalent to man -k.
Basic Usage
Search for Keyword
apropos copy
Shows commands related to "copy".
Multiple Keywords
apropos file copy
Shows commands matching either "file" OR "copy".
Exact Phrase
apropos "copy files"
Searches for the exact phrase.
Common Searches
File Operations
apropos copy
apropos move
apropos delete
apropos rename
apropos compress
Network Commands
apropos network
apropos socket
apropos tcp
apropos wireless
System Administration
apropos user
apropos group
apropos permission
apropos service
apropos process
Text Processing
apropos search
apropos replace
apropos pattern
apropos filter
Options
-s, --section
Search specific manual section:
apropos -s 1 passwd
apropos --section 1 network
Manual sections: - 1: User commands - 2: System calls - 3: Library functions - 4: Special files - 5: File formats and conventions - 6: Games - 7: Miscellaneous - 8: System administration commands
-a, --and
Match ALL keywords (AND logic):
apropos -a copy file
Shows only commands matching both "copy" AND "file".
-e, --exact
Match exact keyword:
apropos -e cp
Matches exactly "cp", not "tcp" or "scp".
-w, --wildcard
Enable wildcard matching:
apropos -w 'net*'
Matches "network", "netstat", etc.
-r, --regex
Use regular expressions:
apropos -r '^net'
apropos --regex 'copy|move'
-i, --ignore-case
Case-insensitive search (default):
apropos -i NETWORK
-l, --long
Don't trim output to terminal width:
apropos -l network
-C, --config-file
Use alternative man configuration:
apropos -C /path/to/man.conf keyword
Practical Examples
Find Copy Commands
apropos copy
Output might include:
cp (1) - copy files and directories
scp (1) - secure copy (remote file copy program)
rsync (1) - fast incremental file transfer
Search for Text Editors
apropos editor
apropos edit
Find Compression Tools
apropos compress
apropos archive
Network Diagnostics
apropos -a network test
apropos ping
apropos trace
User Management
apropos -a user add
apropos password
Find Configuration Files
apropos -s 5 config
Section 5 contains file format descriptions.
Process Management
apropos process
apropos kill
apropos signal
Advanced Usage
Combine with Grep
apropos network | grep wireless
apropos compress | grep -i tar
Multiple Sections
apropos -s 1,8 network
Searches sections 1 and 8 only.
Regex Patterns
# Commands starting with 'net'
apropos -r '^net'
# Commands ending with 'stat'
ap ropos -r 'stat$'
# Commands containing numbers
apropos -r '[0-9]'
Find System Calls
apropos -s 2 file
apropos -s 2 socket
Section 2 contains system calls.
Library Functions
apropos -s 3 string
apropos -s 3 printf
Section 3 contains library functions.
Search Strategies
When You Don't Know the Command
# Want to download files?
apropos download
# Need to monitor system?
apropos monitor
# Want to schedule tasks?
apropos schedule
apropos cron
Troubleshooting
# Network issues
apropos network | grep -E 'test|debug|trace'
# Disk problems
apropos disk | grep -E 'check|repair|scan'
# Performance
apropos performance
apropos benchmark
Discovery
# What can I do with files?
apropos file | less
# What networking tools exist?
apropos network | wc -l # Count them
apropos network | sort # Sort alphabetically
Database Management
Update Database
sudo mandb
Rebuilds the whatis database. Run this if: - Newly installed packages don't show up - apropos returns "nothing appropriate" - Manual pages were recently updated
Check Database Location
manpath
Shows where manual pages are stored.
Comparison with Other Tools
apropos vs man -k
apropos copy
man -k copy
These are identical - apropos is essentially man -k.
apropos vs whatis
# apropos: searches descriptions
apropos copy
# whatis: searches exact command names only
whatis cp
whatis copy # Won't find "cp"
apropos vs which
# apropos: finds commands by description
apropos editor
# which: shows path of executable
which vim
Common Use Cases
Learning New Domain
# Just started with Docker?
apropos docker
# Learning about filesystems?
apropos filesystem
apropos mount
Finding Alternatives
# Want alternatives to ps?
apropos process | grep list
# Other compression tools besides gzip?
apropos compress
Forgotten Commands
# "What was that network tool again?"
apropos -a network interface
# "How do I change permissions?"
apropos permission
apropos chmod
Output Format
Typical output:
cp (1) - copy files and directories
cpan (1) - easily interact with CPAN from the command line
cpio (1) - copy files to and from archives
Format: command (section) - description
Tips and Best Practices
- Start Broad - Begin with general terms, narrow down
- Use Multiple Keywords - Try different related words
- Combine with Grep - Filter results for relevance
- Check Sections - Use
-sto limit to relevant sections - Update Database - Run
sudo mandbif results seem incomplete - Use Regex - Powerful for pattern-based searches
- Read Descriptions - The description helps identify the right tool
- Follow Up with Man - Use
man commandto read full documentation - Case Doesn't Matter - Search is case-insensitive by default
- Try Synonyms - "remove" vs "delete", "list" vs "show"
Troubleshooting
"nothing appropriate" Error
# Rebuild database
sudo mandb
# Check if manual pages exist
ls /usr/share/man/man1/
# Try exact match
apropos -e ls
Too Many Results
# Use AND logic
apropos -a file copy
# Use exact match
apropos -e tar
# Grep for specific term
apropos file | grep compress
Missing Results
# Update database
sudo mandb
# Check manual path
manpath
# Try different keywords
apropos archive # instead of "compress"
Real-World Scenarios
New System Administrator
# What user management commands exist?
apropos user
apropos group
apropos password
# Service management?
apropos service
apropos systemd
Developer
# Debugging tools?
apropos debug
apropos trace
# Build tools?
apropos compile
apropos make
Network Engineer
# Network diagnostics?
apropos -a network test
apropos -a network monitor
# Firewalls?
apropos firewall
apropos iptables
Environment Variables
MANPATH
export MANPATH=/custom/man:/usr/share/man
apropos command
Defines where to search for manual pages.
PAGER
export PAGER=less
apropos network | $PAGER
Integration with Other Tools
With fzf (Fuzzy Finder)
apropos '' | fzf
Interactive search of all commands.
With Rofi/Dmenu
apropos '' | rofi -dmenu -p "Man pages"
GUI selector for commands.
In Scripts
#!/bin/bash
# Find all network-related commands
commands=$(apropos -a network interface | awk '{print $1}')
for cmd in $commands; do
echo "=== $cmd ==="
man "$cmd" | head -n 20
done
Quick Reference
| Command | Description |
|---|---|
apropos keyword |
Search for keyword |
apropos -s 1 keyword |
Search in section 1 |
apropos -a word1 word2 |
Match ALL keywords |
apropos -e exact |
Exact match only |
apropos -r 'regex' |
Regex search |
apropos -w 'wild*' |
Wildcard search |
apropos '' \| less |
Browse all commands |
sudo mandb |
Update database |
man -k keyword |
Same as apropos |
Exit Status
| Code | Meaning |
|---|---|
| 0 | Success, matches found |
| 1 | No matches found |
| 16 | Usage or syntax error |
Manual Page Sections
| Section | Contents |
|---|---|
| 1 | User commands |
| 2 | System calls |
| 3 | Library functions |
| 4 | Special files (devices) |
| 5 | File formats and conventions |
| 6 | Games and demos |
| 7 | Miscellaneous |
| 8 | System administration commands |
| 9 | Kernel routines |