until command in Linux with Examples

until command in Linux is used to execute a set of commands as long as the final command in the 'until' Commands has an exit status that is not zero. It is mostly used where the user needs to execute a set of commands until a condition is true.

Syntax

until COMMANDS; do COMMANDS; done

where,

• CONDITION: The condition that gets checked. If this evaluates to false (non-zero exit status), the loop continues. Once it evaluates to true (zero exit status), the loop terminates.
• COMMANDS: The set of commands that will be executed while the condition is false.

Basic Example of until in Linux

Help Option with until Command

help until: This command displays the help information for until, showing basic syntax and usage. It’s useful for quickly referencing how to use the command in your scripts.

Conclusion

The until command in Linux provides an effective way to execute commands as long as a condition remains false, making it useful in scenarios that require waiting for a specific condition to be met. By understanding its syntax and use cases, you can simplify loop control and automate repetitive tasks efficiently.