Use ps command
Type the following ps command to display all running process
# ps aux | less
Where,
-A: select all processes
a: select all processes on a terminal, including those of other users
x: select processes without controlling ttys
Task: see every process on the system
# ps -A
# ps -e
Task: See every process except those running as root
# ps -U root -u root -N
Task: See process run by user vivek
# ps -u vivek
Task: Use top command
The top program provides a dynamic real-time view of a running system. Type the top at command prompt:
# top
Task: display a tree of processes
pstree shows running processes as a tree. The tree is rooted at either pid or init if pid is omitted. If a user name is specified, all process trees rooted at processes owned by that user are shown.
$ pstree
Task: Print a process tree using ps
# ps -ejH
# ps axjf
Task: Get info about threads
# ps -eLf
# ps axms
Task: Get security info
# ps -eo euser,ruser,suser,fuser,f,comm,label
# ps axZ
# ps -eM
Task: Save Process Snapshot to a file
# top -b -n1 > /tmp/process.log
Or you can email it to yourself:
# top -b -n1 | mail -s ‘Process snapshot’ you@example.com
Task: Lookup process
Use pgrep command. pgrep looks through the currently running processes and lists the process IDs which matches the selection criteria to screen. For example display firefox process id:
$ pgrep firefox
Following command will list the process called sshd which is owned by root user.
$ pgrep -u root sshd
Say hello to htop
htop is interactive process viewer just like top, but allows to scroll the list vertically and horizontally to see all processes and their full command lines. Tasks related to processes (killing, renicing) can be done without entering their PIDs. To install htop type command:
# apt-get install htop
or
# yum install htop
Now type htop to run the command:
# htop
Because It Works!! 