The watch command is a powerful utility available in Unix-like operating systems that allows users to execute a command repeatedly at specified intervals and view the output in real-time. This command can be incredibly useful for monitoring system activity, tracking changes, and observing command output over time.
Getting Started with Watch
To use the watch command, simply open your terminal and type watch followed by the command you want to execute. For example:
watch date
This command will display the current date and time in your terminal, updating every 2 seconds by default. You can customize the update interval by specifying the -n option followed by the desired number of seconds:
watch -n 5 df -h
This command will show disk usage information (df -h) every 5 seconds.
Monitoring System Resources
One common use case for the watch command is monitoring system resources such as CPU usage, memory usage, and disk activity. For example, you can use the following commands to monitor CPU and memory usage in real-time:
watch -n 1 'ps -eo %cpu,%mem,cmd | head -10'
This command will display the top 10 processes consuming CPU and memory every second.
Tracking File Changes
You can also use the watch command to track changes in files or directories. For example, if you want to monitor changes in a specific file, you can use the cat command along with watch:
watch -n 2 'cat /var/log/messages | tail -n 5'
This command will display the last 5 lines of the /var/log/messages file every 2 seconds, allowing you to track new log entries as they occur.
Conclusion
The watch command is a versatile tool that can be used for a wide range of monitoring and tracking tasks in Unix-like systems. By leveraging its capabilities, you can keep an eye on system activity, track changes in files, and more, all from the comfort of your terminal.
Experiment with different commands and options to discover how watch can enhance your workflow and help you stay informed about your system’s status in real-time.
📝 For more information about the watch command, you can refer to the Linux Man Page for this command!
