HowTo: Use ps, kill, nice, and killall To Manage processes in FreeBSD and OS X Unix Operating System

In FreeBSD and OS X, the ps, kill, nice, and killall commands can be used to manage processes on the system.

1. ps: The ps command is used to display information about the currently running processes on the system. To use the ps command, simply type ps at the command prompt. This will display a list of the processes currently running on the system, along with their process IDs (PIDs).

To display more detailed information about the processes, you can use the -A option to show all processes, or the -ax option to show all processes along with their command line arguments. For example:

ps -A

This will display a list of all processes on the system, along with their PIDs and command names.

ps -ax

This will display a list of all processes on the system, along with their PIDs, command names, and command line arguments.

2. kill: The kill command is used to send a signal to a process to terminate it. To use the kill command, type kill followed by the PID of the process you want to terminate. For example:

kill 12345

This will send a signal to the process with PID 12345 to terminate it.

You can also use the -9 option to send a SIGKILL signal, which forces the process to terminate immediately without giving it a chance to clean up. For example:

kill -9 12345

3. nice: The nice command is used to set the priority of a process. By default, processes are given a priority of 0, but you can use the nice command to set a lower or higher priority for a process. To use the nice command, type nice followed by the desired priority and the command you want to run. For example:

nice -n 10 command

This will run the command with a priority of 10, which is lower than the default priority of 0.

4. killall: The killall command is used to terminate all processes with a specific command name. To use the killall command, type killall followed by the command name of the processes you want to terminate. For example:

killall firefox

This will terminate all processes with the command name firefox.

You can also use the -9 option to send a SIGKILL signal, which forces the process to terminate immediately without giving it a chance to clean up. For example:

killall -9 firefox

These are just a few examples of how to use the ps, kill, nice, and killall commands to manage processes in FreeBSD and OS X. For more options and usage examples, you can refer to the man pages for these commands by typing man ps, man kill, man nice, or man killall at the command prompt.