Processes

ps -aux

Full information on all running processes.

USER       PID %CPU %MEM    VSZ   RSS TTY      STAT START   TIME COMMAND
root         1  0.0  0.0 191424  4420 ?        Ss    2019  63:30 /usr/lib/systemd/systemd --switched-root --system --deserialize 22
root         2  0.0  0.0      0     0 ?        S     2019   0:09 [kthreadd]
root         3  0.0  0.0      0     0 ?        S     2019   5:28 [ksoftirqd/0]
root         5  0.0  0.0      0     0 ?        S<    2019   0:00 [kworker/0:0H]
root         7  0.0  0.0      0     0 ?        S     2019   0:05 [migration/0]
root         8  0.0  0.0      0     0 ?        S     2019   0:00 [rcu_bh]
root         9  0.1  0.0      0     0 ?        S     2019 341:06 [rcu_sched]
root        10  0.0  0.0      0     0 ?        S<    2019   0:00 [lru-add-drain]

kill <pid>

Send the TERM signal (usually 9) to the process with PID-<pid>

killall <commandname>

Kill all processes with the name <commandname> this is the name as shown by ps -ef or ps -aux without any options or parameters.