Quickly find and interpret process "nice" values, then adjust priorities safely on a Linux host. 30.11.2025 | reading time: 2 min Want to know which processes are polite and which are greedy? Use simple commands to reveal niceness and understand who gets CPU preference on a system using `ps`, `top`, `nice` and `renice`. A busy worker, a web frontend Case: a background backup script seems to slow down an interactive web worker; list priorities with `ps` and inspect the niceness column; example command and sample output are shown below: ``` $ ps -eo pid,ni,cmd --sort=ni | head -n 12 PID NI CMD 1000 -5 /usr/bin/java -Xmx2g 2001 0 /usr/sbin/nginx: worker process 3012 10 /usr/bin/backup.sh 4023 19 /usr/bin/logrotate ``` Make a change and observe Do it: start a low-priority job and confirm its niceness, then attempt to raise its priority (note: negative niceness requires root); example session: ``` $ nice -n 10 sleep 300 & [1] 12345 $ ps -o pid,ni,cmd -p 12345 PID NI CMD 12345 10 sleep 300 $ sudo renice -n -5 -p 12345 12345: old priority 10, new priority -5 ``` Priority subtleties that matter Niceness uses a -20..19 range where lower is more favorable; it influences CPU scheduling under the CFS scheduler but does not grant real-time guarantees, and negative values require root privileges; for real-time timing use `chrt` and for I/O prioritization use `ionice`. Handy companions for live inspection Watch and filter live: `top` and `htop` let you sort by NI and observe changes, `ps` gives precise snapshots, and `systemctl status` or `journalctl` help correlate priority changes to service events. A clear next move Inspecting niceness gives immediate insight and quick fixes, but mastering scheduling, I/O priority and real-time tools rounds out control; keep experimenting, and consider formalizing skills with certifications like CompTIA Linux+ or LPIC-1 and intensive exam prep at bitsandbytes.academy. Join Bits & Bytes Academy First class LINUX exam preparation. processes utilities troubleshooting
