This guide offers a comprehensive overview of the Linux ‘watch’ command. This simple command allows users to execute a program periodically, watching its output. The article covers the command’s history, major use cases, key parameters, and some little-known tricks. It is an essential part of any Linux enthusiast’s toolkit.
Instructions
This guide offers a detailed exploration of the Linux ‘watch’ command, perfect for beginners. It includes its history, usage, parameters, typical use cases, and some interesting tips and tricks.
History
The ‘watch’ command has been a part of Unix and Unix-like operating systems for many years, providing users with the ability to execute a program periodically, showing output in fullscreen.
When and why to use it
The ‘watch’ command is primarily used when you want to monitor the changes of an executing program over time. It’s especially useful for tracking the progress of operations or changes in file data over time.
How to use it
Using the ‘watch’ command is as simple as typing ‘watch’ followed by the command you want to monitor in the terminal. The command will then be executed every 2 seconds by default.
watch lsThe commonly used parameters
The two most commonly used parameters with the ‘watch’ command are:
-nor-intervalsets the interval at which the command is executed.
watch -n 1 lsdor-differenceshighlights the changes between successive updates.
watch -d lsOther supported parameters
Here are other parameters supported by the ‘watch’ command:
-tor-no-titleturns off the header showing the interval, command, and current time.-bor-beepbeeps if the command has a non-zero exit.
Most common use cases
One of the most common use cases for the ‘watch’ command is to monitor changes in a directory or file. For example, you can use it to monitor the progress of a file download or observe changes in system directories.
watch -n 1 -d ls -lThe tricky skills
One nifty trick with the ‘watch’ command is to use it in combination with other commands to monitor changes in their output over time. You can use it to keep an eye on system processes, user sessions, or network status.
What needs to be noted
Remember that the ‘watch’ command executes other programs, so be careful when using it with commands that change system settings or manipulate data. Also, the ‘watch’ command may not reflect changes instantly if the interval is set too long.
Conclusion
All in all, the ‘watch’ command is a simple but essential part of any Linux user’s toolbox. It provides a straightforward way to monitor changes in the output of commands or files, making it indispensable for tracking progress or diagnosing issues.
