whatis

Overview

The whatis command displays one-line manual page descriptions. It’s useful for quickly finding out what a command does without reading the full manual page.

Syntax

whatis [options] name ...

Common Options

Option	Description
`-d`	Debug mode
`-v`	Verbose mode
`-w`	Match whole words only
`-r`	Use regex for matching
`-l`	List format output
`-s section`	Search only specified sections
`-m system`	Search alternate system
`--long`	Don’t trim output to terminal width

Key Use Cases

Quick command reference
Command discovery
Brief command descriptions
Manual section lookup
Command verification

Examples with Explanations

Example 1: Basic Usage

whatis ls

Show description of ls command

Example 2: Multiple Commands

whatis cp mv rm

Show descriptions for multiple commands

Example 3: Regex Search

whatis -r '^zip.*'

Find all commands starting with ‘zip’

Understanding Output

Format:

command (section) - description

Example:

ls (1) - list directory contents

Common Usage Patterns

Check command purpose:
```
whatis command
```
Find related commands:
```
whatis -w "*pdf*"
```
Search specific section:
```
whatis -s 1 command
```

Performance Analysis

Fast command lookup
Database-driven searches
Regular expression support
Section-specific searches
Multiple command lookup