Using the `whatis` Command (with examples)

Introduction

The whatis command is a useful tool that allows users to search a set of database files containing short descriptions of system commands for specific keywords. This command provides a quick way to find information about different commands in the system, making it easier for users to understand their functionality and usage.

In this article, we will explore different use cases of the whatis command along with code examples, motivations, explanations for each argument, and example outputs.

Searching for Information about a Keyword

To search for information about a specific keyword, you can simply use the whatis command followed by the keyword. The command will then search the database files for a match and display the short description of the command.

Code Example:

whatis keyword

Motivation:

Using the whatis command to search for information about a keyword can be helpful when you are unsure about the purpose or functionality of a specific command. By providing a short description, the command enables users to quickly determine what a command does.

Explanation:

• whatis: The command itself.
• keyword: The keyword or command name you want to search for in the database files.

Example Output:

Suppose we want to know more about the ls command. We can use the following command:

whatis ls

The output of this command would be something like:

ls (1)              - list directory contents

This output tells us that the ls command is used to list the contents of a directory.

Searching for Information about Multiple Keywords

The whatis command also allows you to search for information about multiple keywords at once. This can be useful when you have more than one keyword and want to find information about all of them in a single command.

Code Example:

whatis keyword1 keyword2

Motivation:

Searching for information about multiple keywords can save time and effort, especially when you have a list of commands and want to know their functionalities all at once. Instead of running separate whatis commands for each keyword, you can use a single command to obtain the information for all of them.

Explanation:

• whatis: The command itself.
• keyword1 keyword2: Multiple keywords or command names you want to search for in the database files.

Example Output:

Suppose we want to search for information about both the cat and grep commands. We can use the following command:

whatis cat grep

The output of this command would be something like:

cat (1)             - concatenate files and print on the standard output
grep (1)            - print lines that match patterns

This output tells us that the cat command is used to concatenate files and print their contents, while the grep command is used to search for lines that match patterns.

Conclusion

The whatis command is a powerful tool for searching database files containing short descriptions of system commands. With its ability to search for information about keywords and multiple keywords at once, it provides a quick and efficient way to understand the functionality and usage of various commands in the system.

By utilizing the code examples, motivations, explanations, and example outputs provided in this article, you can effectively use the whatis command to explore and learn more about different commands in your system.