Linux nice command

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Linux nice command executes programs with the changed priority, if no program is specified, it will print the current scheduling priority, and the default adjustment is 10, ranging from -20 (Highest priority) to 19(Lowest priority).

Usage Permissions: All users.

Syntax

nice [-n adjustment] [-adjustment] [--adjustment=adjustment] [--help] [--version] [command [arg...]]

Parameter Description:

• -n adjustment, -adjustment, --adjustment=adjustment Both are to increase the original priority by adjustment
• --help Display Help Messages
• --version Display Version Information

Online Examples

Set Program Priority at Runtime

# vi & //Run in Background
[1] 15297
# nice vi & //Set Default Priority
[2] 15298
[1]+ Stopped         vi
# nice -n 19 vi & //Set Priority to19
[3] 15299
[2]+ Stopped         nice vi
# nice -n -20 vi & //Set Priority to -20
[4] 15300
[3]+ Stopped         nice -n 19 vi
# ps -l //Display Processes
F S  UID  PID PPID C PRI NI ADDR SZ WCHAN TTY     TIME CMD
4 S   0 15278 15212 0 80  0 - 1208 wait  pts/2  00:00:00 bash
0 T   0 15297 15278 0 80  0 - 2687 signal pts/2  00:00:00 vi
0 T   0 15298 15278 0 90 10 - 2687 signal pts/2  00:00:00 vi
0 T   0 15299 15278 1 99 19 - 2687 signal pts/2  00:00:00 vi
4 T   0 15300 15278 3 60 -20 - 2687 signal pts/2  00:00:00 vi
4 R   0 15301 15278 0 80  0 -  625 -   pts/2  00:00:00 ps
[4]+ Stopped         nice -n -20 vi

Increase the priority of ls 1 and execute

nice -n 1 ls

Increase the priority of ls 10 and execute

nice ls

Note:Priority (priority) is a parameter used by the operating system to decide CPU allocation, Linux uses 'round-robin(round-The CPU scheduling is done using Robin's algorithm, the higher the priority, the more CPU time it may obtain.

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