Processes

Overview

Here’s an example workflow:

List all processes:
```
ps aux
```
or
```
top
```
or
```
htop
```
Filter processes by name:
```
ps aux | grep process_name
```
or use top/htop with filters to search for the process. It can be killed from there too.
Find the PID of the process using pgrep:
```
pgrep process_name
```
or note the PID from top/htop.
Stop the process:
```
kill process_id
```
If the process doesn’t stop, force kill it:
```
kill -9 process_id
```

Always exercise caution when stopping or killing processes, especially system processes, as it may lead to unintended consequences.

List Processes

Non-interactive

To list all processes running on the system, use the ps command:

ps aux

This will display a list of processes with details like process ID (PID), user, CPU and memory usage, and the command that started the process.

Interactive

top and htop provide an interactive interface to monitor processes, CPU and memory usage, and other system information.

You can use top (builtin) or htop (3rd-party) to get a real-time view of running processes:

top

htop

Press q to exit.

Filtering Processes

You can filter the output of ps using grep. For example, to filter processes by name:

ps aux | grep process_name

Replace process_name with the actual name of the process you want to filter.

e.g.

> ps aux | grep redis
michael.currin   21896   0.1  0.0 411066704   1712 s000  S+   Mon03PM   1:29.69 redis-server *:6379
michael.currin   46092   0.0  0.0 410774336    560 s013  S+   Tue04PM   0:00.10 redis-cli
michael.currin   71866   0.0  0.0 410059824    240 s004  R+    9:25AM   0:00.00 grep redis

Alternatively, you can use pgrep to find the PID of a process by name:

pgrep process_name

This will return the PID(s) of the process(es) matching the given name.

e.g.

> pgrep redis
21896
46092

Stopping or Killing Processes

To stop or kill a process, you need to know its PID. You can use the kill command followed by the PID:

kill process_id

This will send a termination signal to the process. If the process doesn’t terminate gracefully, you can use the -9 option to force kill it:

kill -9 process_id

Alternatively, you can use the pkill command to kill a process by name:

pkill process_name

Be careful when killing processes, as it may lead to data loss or system instability if critical processes are terminated.