getkey Command in Linux

The getkey command, as a simple utility for capturing a single character from the keyboard, doesn't have specific options. It's designed to be straightforward and minimal, focusing solely on its primary function.

The getkey command can be used in a variety of situations, such as: Pausing a script for user confirmation before executing a critical operation. Creating a timeout feature for user input in a script.

Here's a detailed look at how getkey works and some examples of its usage.

Table of Contents

Here is a comprehensive guide to the options available with the getkey command −

• Understanding getkey Command
• How to Use getkey Command in Linux?
• Options Available with the getkey Command
• Examples of Using the getkey Command

Understanding getkey Command

The getkey command is a simple yet powerful tool that can be incorporated into scripts to enhance interactivity and control flow based on user input. Understanding and utilizing its options can greatly aid in creating more dynamic and user-friendly scripts in Linux.

For more detailed information and examples, you can refer to the man page or other documentation available for the getkey command in Linux. Remember to always test your scripts in a safe environment to ensure they behave as expected with the getkey command and its options.

How to Use getkey Command in Linux?

The getkey command operates by waiting for a specific key or any key to be pressed, depending on the arguments provided. It's particularly useful in scenarios where a script needs to pause for user interaction before proceeding.

The getkey command in Linux is a utility that waits for a key press from the user and can be quite useful in scripting and programming when user interaction is required.

Syntax

Without any arguments, getkey will wait for any key press and exit immediately once a key is pressed.

The basic syntax of the getkey command is as follows −

getkey [OPTION]... [KEYS]

KEYS − After the options, you can specify a list of keys that getkey will accept. If no keys are specified, it will accept any key press. The keys are matched in a case-insensitive manner.

The getkey command exits with different statuses based on the outcome −

• It exits with status 0 if one of the expected keys is pressed.
• It exits with status 255 if invalid arguments are specified.
• For other interruptions or timeouts, it exits with a non-zero status.

Options Available with the getkey Command

Here's a detailed look at the options available with the getkey command −

Examples of Using the getkey Command

The getkey command in Linux is a utility that waits for a key press and exits after a key is pressed. It's a simple yet powerful tool that can be used in various scenarios, such as scripting and user input handling.

Basic Usage without Arguments

The getkey command in Linux is a utility that waits for a key press from the user. Without any arguments, getkey will wait indefinitely until any key is pressed.

getkey

This command will wait indefinitely until any key is pressed.

Waiting for a Specific Key

You can specify which keys getkey should wait for by listing them after the command.

getkey a

Here, getkey will only exit when the 'a' key is pressed.

Setting a Time Limit

This option sets a time limit for the wait in seconds. If no key is pressed within the specified time, getkey exits. The -c option allows you to set a time limit in seconds for how long getkey will wait for a key press.

getkey -c 5

getkey will wait for 5 seconds for a key press and exit even if no key is pressed.

Displaying a Message

A message will be displayed, counting down from 5 seconds, prompting the user to press a key:

getkey -c 5 -m "Press a key within %d seconds"

Ignoring Control Characters

By default, control characters like Ctrl+C and Ctrl+D interrupt the getkey. This option allows getkey to ignore these interruptions. By default, getkey treats Ctrl+C and Ctrl+D specially. The -i option can be used to ignore these control characters.

getkey -i

Displaying a Message

With the -m option, you can display a message while waiting for a key press. The message can include a format string to show the number of seconds left if a time limit is set.

getkey -c 10 -m "Press a key within %d seconds"

Combining Options

It's a simple yet powerful tool that can be used in shell scripts and terminal applications to pause execution until the user provides input. You can combine multiple options to customize the behavior of getkey.

getkey -c 5 -i -m "Press any key to continue"

Capturing a Single Character

This script prompts the user to press any key, captures the input using getkey, and then displays the pressed character.

#!/bin/bash

echo "Press any key to continue..."
key=$(getkey)

echo "You pressed: $key"

This script provides a choice to the user and executes different actions based on the pressed key.

Conclusion

The getkey command is a versatile tool that can enhance interactivity in shell scripts and terminal applications. Its ability to wait for user input with or without a time limit makes it suitable for a wide range of use cases.

By understanding and utilizing the options available with getkey, users can create more dynamic and user-friendly scripts.