kodingwindow@kw:~$ ps
    PID TTY          TIME CMD
   3368 pts/0    00:00:00 bash
   3372 pts/0    00:00:00 ps

kodingwindow@kw:~$ ps -a
    PID TTY          TIME CMD
   2377 tty2     00:00:08 Xorg
   2417 tty2     00:00:00 gnome-session-b
   3373 pts/0    00:00:00 ps

kodingwindow@kw:~$ ps -aux
USER         PID %CPU %MEM    VSZ   RSS TTY      STAT START   TIME COMMAND
root           1  0.5  0.1 167952 11684 ?        Ss   18:24   0:01 /sbin/init sp
root           2  0.0  0.0      0     0 ?        S    18:24   0:00 [kthreadd]
root           3  0.0  0.0      0     0 ?        I<   18:24   0:00 [rcu_gp]
root           4  0.0  0.0      0     0 ?        I<   18:24   0:00 [rcu_par_gp]
root           5  0.3  0.0      0     0 ?        I    18:24   0:01 [kworker/0:0-
root           6  0.0  0.0      0     0 ?        I<   18:24   0:00 [kworker/0:0H
.
.
.
root        3380  0.0  0.0  24724  5840 ?        S    18:30   0:00 /lib/systemd/
root        3579  0.0  0.0   9492  3348 ?        S    18:30   0:00 /bin/bash /et
root        3585  0.0  0.0   8272   776 ?        S    18:30   0:00 flock --nonbl
root        3586  4.5  0.0   8168  2328 ?        DN   18:30   0:00 /usr/bin/upda
kodingw+    3587  0.0  0.0  11888  3724 pts/0    R+   18:30   0:00 ps -aux
kodingwindow@kw:~$ 

kodingwindow@kw:~$ ps -e
    PID TTY          TIME CMD
      1 ?        00:00:02 systemd
      2 ?        00:00:00 kthreadd
      3 ?        00:00:00 rcu_gp
      4 ?        00:00:00 rcu_par_gp
      5 ?        00:00:01 kworker/0:0-events
      6 ?        00:00:00 kworker/0:0H-kblockd
      8 ?        00:00:01 kworker/u8:0-events_unbound
      9 ?        00:00:00 mm_percpu_wq
     10 ?        00:00:00 ksoftirqd/0

kodingwindow@kw:~$ ps -eo pid,ppid,ni
    PID    PPID  NI
      1       0   0
      2       0   0
      3       2 -20
      4       2 -20
      5       2   0
      6       2 -20
      8       2   0
      9       2 -20

kodingwindow@kw:~$ ps aux --sort user
USER         PID %CPU %MEM    VSZ   RSS TTY      STAT START   TIME COMMAND
avahi        949  0.0  0.0   8808  3676 ?        Ss   18:25   0:00 avahi-daemon:
avahi       1003  0.0  0.0   8544   356 ?        S    18:25   0:00 avahi-daemon:
kodingw+    2286  0.0  0.1  19472 10760 ?        Ss   18:26   0:00 /lib/systemd/
kodingw+    2287  0.0  0.0 169324  3816 ?        S    18:26   0:00 (sd-pam)
kodingw+    2300  0.0  0.2 2268840 19676 ?       S<sl 18:27   0:00 /usr/bin/puls
kodingw+    2302  0.0  0.3 511384 24320 ?        SNsl 18:27   0:00 /usr/libexec/
kodingw+    2305  0.0  0.0   8452  5624 ?        Ss   18:27   0:00 /usr/bin/dbus
kodingw+    2310  0.0  0.0 240184  7716 ?        Sl   18:27   0:00 /usr/bin/gnom
kodingw+    2325  0.0  0.0 239696  7820 ?        Ssl  18:27   0:00 /usr/libexec/

kodingwindow@kw:~$ ps -aux | grep mysql
mysql       1172  1.1  4.4 2120856 352952 ?      Ssl  18:25   0:04 /usr/sbin/mysqld
kodingw+    3607  0.0  0.0   8900   724 pts/0    S+   18:32   0:00 grep mysql

kodingwindow@kw:~$ pgrep mysql
1172

kodingwindow@kw:~$ pgrep -l mysql
1172 mysqld

kodingwindow@kw:~$ ps -lp 1172
F S   UID     PID    PPID  C PRI  NI ADDR SZ WCHAN  TTY          TIME CMD
4 S   122    1172       1  1  80   0 - 530214 -     ?        00:00:10 mysqld

kodingwindow@kw:~$ su
Password: 
root@kw:/home/kodingwindow#  ps -l
F S   UID     PID    PPID  C PRI  NI ADDR SZ WCHAN  TTY          TIME CMD
4 S     0    4426    4424  0  80   0 -  2875 do_wai pts/0    00:00:00 su
4 S     0    4427    4426  0  80   0 -  2546 do_wai pts/0    00:00:00 bash
4 R     0    4440    4427  0  80   0 -  2849 -      pts/0    00:00:00 ps
root@kw:/home/kodingwindow#  nice
0
root@kw:/home/kodingwindow#  nice -n 5 bash
root@kw:/home/kodingwindow#  ps -l
F S   UID     PID    PPID  C PRI  NI ADDR SZ WCHAN  TTY          TIME CMD
4 S     0    4426    4424  0  80   0 -  2875 do_wai pts/0    00:00:00 su
4 S     0    4427    4426  0  80   0 -  2546 do_wai pts/0    00:00:00 bash
0 S     0    4442    4427  0  85   5 -  2545 do_wai pts/0    00:00:00 bash
4 R     0    4453    4442  0  85   5 -  2849 -      pts/0    00:00:00 ps
root@kw:/home/kodingwindow#  renice -0 4442
4442 (process ID) old priority 5, new priority 0

root@kw:/home/kodingwindow#  ps -l
F S   UID     PID    PPID  C PRI  NI ADDR SZ WCHAN  TTY          TIME CMD
4 S     0    4426    4424  0  80   0 -  2875 do_wai pts/0    00:00:00 su
4 S     0    4427    4426  0  80   0 -  2546 do_wai pts/0    00:00:00 bash
0 S     0    4442    4427  0  80   0 -  2545 do_wai pts/0    00:00:00 bash
4 R     0    4455    4442  0  80   0 -  2849 -      pts/0    00:00:00 ps


root@kw:/home/kodingwindow#  renice -21 4442
4442 (process ID) old priority 0, new priority -20

root@kw:/home/kodingwindow#  ps -l
F S   UID     PID    PPID  C PRI  NI ADDR SZ WCHAN  TTY          TIME CMD
4 S     0    4426    4424  0  80   0 -  2875 do_wai pts/0    00:00:00 su
4 S     0    4427    4426  0  80   0 -  2546 do_wai pts/0    00:00:00 bash
0 S     0    4442    4427  0  60 -20 -  2545 do_wai pts/0    00:00:00 bash
4 R     0    4476    4442  0  60 -20 -  2849 -      pts/0    00:00:00 ps
root@kw:/home/kodingwindow#  

kodingwindow@kw:~$ pstree
systemd─┬─ModemManager───2*[{ModemManager}]
        ├─NetworkManager───2*[{NetworkManager}]
        ├─accounts-daemon───2*[{accounts-daemon}]
        ├─acpid
        ├─avahi-daemon───avahi-daemon
        ├─bluetoothd
        ├─colord───2*[{colord}]
        ├─cron
        ├─cups-browsed───2*[{cups-browsed}]
        ├─cupsd
        ├─dbus-daemon
        ├─gdm3─┬─gdm-session-wor─┬─gdm-x-session─┬─Xorg───13*[{Xorg}]
        │      │                 │               ├─gnome-session-b─┬─ssh-agent
        │      │                 │               │                 └─2*[{gnome-+
        │      │                 │               └─2*[{gdm-x-session}]
        │      │                 └─2*[{gdm-session-wor}]
        │      └─2*[{gdm3}]
        ├─geoclue───2*[{geoclue}]
        ├─gnome-keyring-d───3*[{gnome-keyring-d}]
        ├─ibus-daemon─┬─ibus-dconf───3*[{ibus-dconf}]
        │             ├─ibus-engine-sim───2*[{ibus-engine-sim}]
        │             ├─ibus-extension-───3*[{ibus-extension-}]
        │             ├─ibus-ui-gtk3───3*[{ibus-ui-gtk3}]
...  

kodingwindow@kw:~$ top
top - 18:38:14 up 13 min,  1 user,  load average: 0.63, 0.87, 0.87
Tasks: 224 total,   1 running, 223 sleeping,   0 stopped,   0 zombie
%Cpu(s):  4.7 us,  2.0 sy,  0.0 ni, 93.1 id,  0.0 wa,  0.0 hi,  0.2 si,  0.0 st
MiB Mem :   7744.8 total,   4550.7 free,   1583.5 used,   1610.6 buff/cache
MiB Swap:   3815.0 total,   3815.0 free,      0.0 used.   5675.2 avail Mem 

    PID USER      PR  NI    VIRT    RES    SHR S  %CPU  %MEM     TIME+ COMMAND  
   3099 kodingw+  20   0 2987604 367320 170248 S   8.0   4.6   0:40.19 MainThr+ 
   2377 kodingw+  20   0 1143856  87276  54980 S   7.0   1.1   0:32.62 Xorg     
   2629 kodingw+  20   0 4488208 257140 101068 S   6.0   3.2   0:40.69 gnome-s+ 
   3357 kodingw+  20   0  962192  51452  39424 S   3.0   0.6   0:08.14 gnome-t+ 
   3296 kodingw+  20   0 2684072 250256 153392 S   2.0   3.2   0:18.56 Web Con+ 
    433 root     -51   0       0      0      0 S   1.0   0.0   0:02.03 irq/87-+ 
      1 root      20   0  167952  11684   8228 S   0.7   0.1   0:02.50 systemd  
   1172 mysql     20   0 2120856 352952  33540 S   0.7   4.5   0:08.17 mysqld   
   2506 kodingw+  20   0  311420   7728   6056 S   0.7   0.1   0:03.57 ibus-da+ 
   3737 kodingw+  20   0   12168   4240   3444 R   0.7   0.1   0:00.14 top      
      8 root      20   0       0      0      0 I   0.3   0.0   0:01.17 kworker+ 
   2515 kodingw+  20   0  674584  58852  39052 S   0.3   0.7   0:01.86 ibus-ex+ 
   2592 kodingw+  20   0  162684   7048   6412 S   0.3   0.1   0:00.99 ibus-en+ 
   3203 kodingw+  20   0 2765492 248912 139908 S   0.3   3.1   1:08.42 Web Con+ 
   3610 root      20   0       0      0      0 I   0.3   0.0   0:00.56 kworker+ 
      2 root      20   0       0      0      0 S   0.0   0.0   0:00.00 kthreadd 
      3 root       0 -20       0      0      0 I   0.0   0.0   0:00.00 rcu_gp