ps [-AaCcEefhjlMmrSTvwXx]
   [-O fmt | -o fmt]
   [-G gid [,gid...]]
   [-g grp [,grp...]]
   [-u uid [,uid...]]
   [-p pid [,pid...]]
   [-t tty [,tty...]] [-U user [,user...]]

For the processes which have been selected for display, the default information to display includes:
The process ID (PID), the controlling terminal (TTY), the CPU time the process has used, and the associated command.

The ps command supports three different types of options:

• Unix-style options: they are preceded by a dash character (-f, ...).
  
• BSD-style options: they are not preceded by a dash character (x, ...).
  
• GNU long options: they are preceded by a double dash characters (--forest, ...).
  

Here's a list of some the headers that are displayed by the ps command:

• UID: the user that started the process.
  
• PID: the process ID.
  
• PPID: the process ID of the parent of the process.
  
• C: the utilization of the processor.
  
• STIME: the system time when the process started.
  
• TTY: the terminal that started the process.
  
• TIME: the total time required to run the process.
  
• CMD: the command that started the process.
  

Extra headers can be shown with the option -l:

• F: the system flags assigned to the process by the kernel.
  
• S: the state of the process (O: running, S: sleeping, R: runnable, Z: zombie, T: stopped).
  
• PRI: the priority of the process (lower numbers means higher priority).
  
• NI: the nice value.
  
• ADDR: the memory address of the process.
  
• SZ: the swap space required by the process.
  
• WCHAN: the address of the kernel where the process is sleeping.
  

The BSD-style option l show a special header STAT that display the state of the process using two characters:

• The first character shows the state of the process (O: running, S: sleeping, R: runnable, Z: zombie, T: stopped).
  
• The second character shows the status of the process:
  
  • <: the process is running at high priority.
    
  • N: the process is running at low priority.
    
  • L: the process has pages locked in memory.
    
  • s: the process is a session leader.
    
  • l: the process is multi-threaded.
    
  • +: the process is running in the foreground.
    

• List processes that belongs to the current user and running on the current terminal:
  
  
  • Default output:
    

    $ ps
     PID TTY          TIME CMD
    5355 pts/0    00:00:00 bash
    7719 pts/0    00:00:00 ps

    
    
  • Full-format:
    

    $ ps -f
    UID        PID  PPID  C STIME TTY          TIME CMD
    mtitek    5355  5354  0 14:57 pts/0    00:00:00 -bash
    mtitek    7706  5355  0 18:51 pts/0    00:00:00 ps -f

    
    
  • Long format (Unix-style option):
    

    $ ps -l
    F S   UID   PID  PPID  C PRI  NI ADDR SZ WCHAN  TTY          TIME CMD
    0 S  1000  5355  5354  0  80   0 -  5732 wait   pts/0    00:00:00 bash
    0 R  1000  7708  5355  0  80   0 -  7230 -      pts/0    00:00:00 ps

    
    
  • Long format (BSD-style option):
    

    $ ps l
    F   UID   PID  PPID PRI  NI    VSZ   RSS WCHAN  STAT TTY        TIME COMMAND
    0  1000  5355  5354  20   0  22928  5512 wait   Ss   pts/0      0:00 -bash
    0  1000  9642  5355  20   0  28920  1484 -      R+   pts/0      0:00 ps l

    
    
• List processes that belongs to the current user including processes without a terminal device assigned:
  

  $ ps x
   PID TTY      STAT   TIME COMMAND
  5258 ?        Ss     0:00 /lib/systemd/systemd --user
  5259 ?        S      0:00 (sd-pam)
  5354 ?        R      0:00 sshd: mtitek@pts/0
  5355 pts/0    Ss     0:00 -bash
  7980 pts/0    R+     0:00 ps x

  
  
• Display processes hierarchy (the relationship between processes is drawn using ASCII characters):
  

  $ ps x --forest
   PID TTY      STAT   TIME COMMAND
  5354 ?        S      0:00 sshd: mtitek@pts/0
  5355 pts/0    Ss     0:00  \_ -bash
  8128 pts/0    R+     0:00      \_ ps x --forest
  5258 ?        Ss     0:00 /lib/systemd/systemd --user
  5259 ?        S      0:00  \_ (sd-pam)

  
  
• List all processes:
  

  $ ps -e

  
  

  $ ps -A

  
  
• List PID processes:
  

  $ ps | grep bash | grep -v grep | awk '{print $1}'
  17190

  $ ps | grep bash | grep -v grep | awk {'print $1 " " $2 " " $3 " " $4 " " $5 '}
  17190 pts/0 00:00:00 bash

  
  

  $ ps | grep bash | grep -v grep | colrm 6
  17190

  
  

  $ for pid in `ps -e -f | grep mongodb | grep -v grep | awk '{print $2}'`; do echo "PID: $pid"; done
  PID: 19034

  
  
• Kill processes:
  

  $ for pid in `ps -e -f | grep mongodb | grep -v grep | awk '{print $2}'`; do kill -9 $pid; done

Basic options:

-A, -e               all processes
-a                   all with tty, except session leaders
 a                   all with tty, including other users
-d                   all except session leaders
-N, --deselect       negate selection
 r                   only running processes
 T                   all processes on this terminal
 x                   processes without controlling ttys

Selection by list:

-C <command>         command name
-G, --Group <GID>    real group id or name
-g, --group <group>  session or effective group name
-p, p, --pid <PID>   process id
       --ppid <PID>  parent process id
-q, q, --quick-pid <PID> process id (quick mode)
-s, --sid <session>  session id
-t, t, --tty <tty>   terminal
-u, U, --user <UID>  effective user id or name
-U, --User <UID>     real user id or name

The selection options take as their argument either:
- a comma-separated list e.g. '-u root,nobody'
- or a blank-separated list e.g. '-p 123 4567'

Output formats:

-F                   extra full
-f                   full-format, including command lines
 f, --forest         ascii art process tree
-H                   show process hierarchy
-j                   jobs format
 j                   BSD job control format
-l                   long format
 l                   BSD long format
-M, Z                add security data (for SELinux)
-O <format>          preloaded with default columns
 O <format>          as -O, with BSD personality
-o, o, --format <format> user-defined format
 s                   signal format
 u                   user-oriented format
 v                   virtual memory format
 X                   register format
-y                   do not show flags, show rss vs. addr (used with -l)
    --context        display security context (for SELinux)
    --headers        repeat header lines, one per page
    --no-headers     do not print header at all
    --cols, --columns, --width <num> set screen width
     --rows, --lines <num> set screen height

Show threads:

 H                   as if they were processes
-L                   possibly with LWP and NLWP columns
-m, m                after processes
-T                   possibly with SPID column

Miscellaneous options:

-c                   show scheduling class with -l option
 c                   show true command name
 e                   show the environment after command
 k,    --sort        specify sort order as: [+|-]key[,[+|-]key[,...]]
 L                   show format specifiers
 n                   display numeric uid and wchan
 S,    --cumulative  include some dead child process data
-y                   do not show flags, show rss (only with -l)
-V, V, --version     display version information and exit
-w, w                unlimited output width

       --help <simple|list|output|threads|misc|all> display help and exit