pidof and pgrep examples and turorails

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pidof and pgrep examples and turorails:
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===>> pidof :  Find the process ID of a running program
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-s : Single shot- this instruct the program to only return one pid.
    It will return only One pid
-o : Tell pidof to omit processes with that process id.
    It Ommit the pid.

Example :
#pidof -o 1123  mingetty  (If there are 4 process of mintetty, So the cmd will ommit the pid provided)
for example: it is used when you do not want to kill specific pid's
ex: #pidof -o 1123 12345 mingetty

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===>> pgrep:  look up or singnal processess  based on name and other attributes.
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Both commands(pidof and pgrep) will show the process id for the command mingetty
ex:
#pidof mingetty
or
#pgrep mingetty
pidof <command>
or
pgrep <command>

1) #pgrep -u root sshd
will only list the process called sshd AND OWNED By root.

2) #pgrep -u root,bob
will list the processes owned by root or bob users.

3) #pgrep -d " " -u root
-d delimiter: list all the process after space..

4) #pgrep -l -u root
-l : List the process name as wll as there PIDS

5) #pgrep -n <cmd>
print the latest pid for the process(cmd),
-n Select only the newet (most recent started) for matching process.

6) #pgrep -o <cmd>
-o Select only the oldest (least recent started) for matching process.

=> Assuming that the process Id 7 is for kthread cmd(It is system cmd)
  #pgrep -l kthread
7) #pgrep -P 7 -l     (It will list all the child processess for the Main process(kthread)) and list the cmd as well as its pid
-P : Only match process whose parent process ID is listed:

8) #pgrep -u root -v -l  (Will not list the processes by user root)
List all the running process and it name owned by all users except root
-v negate

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