Use the watch utility to rerun and observe command output so he can spot changes live. 16.11.2025 | reading time: 2 min On the command line, `watch` reruns a given command at regular intervals and redraws the terminal so he can observe changes as they happen; simple to start, powerful in practice. See disk usage update Case example: monitor disk usage every two seconds to catch sudden fills by running the command inside `watch`; example shown here uses a code block to show the exact invocation and sample output ```$ watch -n 2 df -h Every 2.0s: df -h Filesystem Size Used Avail Use% Mounted-on /dev/sda1 50G 30G 18G 63% / tmpfs 1.0G 0 1.0G 0% /run /dev/sdb1 200G 150G 40G 79% /data ``` Highlight changes and tweak interval Try `-n` to change the interval, `-d` to highlight differences between updates, and `-t` to remove the header so only the command output shows; for example he can run `watch -n 5 -d -t "ss -tuln"` to watch network sockets with changes emphasized. Practical tips and caveats Remember that `watch` executes commands under `/bin/sh` so use quoting for pipelines or complex expressions, avoid very short intervals for expensive commands, and prefer `-g` when you want `watch` to exit on the first output change; for more advanced logic he can wrap commands in scripts or use a shell loop instead. When to reach for other tools For interactive process exploration or persistent multiplexing pick specialized tools instead of `watch`; use `watch` for quick polling and spot checks, but use `htop` for interactive process control, `tmux` to keep sessions alive, or `tail` for streaming logs when needed. Next steps Start with small, safe commands and increase complexity as he becomes comfortable, then combine `watch` with scripts to automate monitoring tasks; consider deepening skills and pursuing certifications such as CompTIA Linux+ or LPIC-1 with intensive exam preparation at bitsandbytes.academy. Join Bits & Bytes Academy First class LINUX exam preparation. utilities processes troubleshooting
