watch

Watch

The watch command is a utility that allows you to run a command repeatedly over time, displaying its output each time it runs. It’s often used to monitor system processes, network traffic, or file system activity.

Use cases:

• Monitoring a specific process: You can use watch to run ps aux every few seconds to see the list of running processes change.
• Watching log files: Run watch tail -f /var/log/syslog to see new log messages as they appear.
• Observing system resource usage: Use watch top or watch htop to monitor CPU, memory, and other resources in real-time.

Special hacks:

• To only run the command every 10 seconds when the screen is not updated (e.g., when the output doesn’t change), use watch -n 10. This can help save system resources.
• Use watch -d to highlight any changes in the output, making it easier to spot differences.

Experience level:

The watch command is suitable for users at an intermediate level (2-3 on a scale of 1-5). While beginners might find it useful, they may not fully understand its power and flexibility. More advanced users will appreciate the ability to combine watch with other commands and filters.

Tips for beginners:

• Start by using simple commands like watch ps aux or watch top.
• Experiment with different intervals (e.g., -n 5, -n 10) to find the right balance between update frequency and system resource usage.
• Use man watch and explore online resources for more examples and use cases.