Linux / UNIX: Find out or determine if process pid is running

by nixCraft on August 21, 2007 · 17 comments· last updated at August 21, 2007

Q. How do I find out my process is running? How do I get pid number for particular process?

A. The easiest way to find out is run ps aux command and grep process name. If you got output along with process name/pid, your process is running.

Task: Find out process pid

Simply use ps command as follows:
ps aux | grep {process-name}
For example find out if mysqld process (mysqld pid) is running or not:
$ ps aux | grep mysqld
Output:

mysql    28290  1.1  2.7 340496 56812 ?        Sl   Jul31 348:27 /usr/libexec/mysqld --defaults-file=/etc/my.cnf --basedir=/usr --datadir=/var/lib/mysql --user=mysql --pid-file=/var/run/mysqld/mysqld.pid --skip-locking --socket=/var/lib/mysql/mysql.sock

Find the process ID of a running program using pidof

pidof command finds the process id’s (pids) of the named programs. It prints those id’s on screen. This program is on some systems used in run level change scripts, especially when the system has a System-V like rc structure. In that case these scripts are located in /etc/rc?.d, where ? is the runlevel. If the system has a start-stop-daemon (8) program that should be used instead.
# pidof mysqld
Output:

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{ 17 comments… read them below or add one }

1 surendra kumar August 27, 2007 at 8:14 am

hay man you can use pgrep also know?
why ps -aux | grep process name?
u can use pgrep like this
pgrep process name
pgrep httpd
pgrep named
pgrep firefox
etc
if any special about your command just give me info related to it

2 Adrian B. February 10, 2009 at 9:27 am

Thanks Surendra, damn good tips

3 Adrian B. February 10, 2009 at 9:28 am

you can also use this :
$>pkill -f cruisecontrol
in a cruisecontrol process which runs under java. -f does a substring search of the process string.

4 lala September 20, 2009 at 7:33 pm

man, u guys rock, trust me it helps so much, when my maya hangs.
special thanks: adrian B, pkill -f maya: wow, toogood

5 Rakesh October 2, 2009 at 11:40 am

Hi .

I have a probleam . when i start mysql it is showing MySQL manager or server PID file could not be found! [FAILED] . Starting MySQL/etc/init.d/mysql: line 159: kill: (5984) – No such process .how to solve the probleam. if any one know plz help me

6 subramanya April 23, 2010 at 8:38 am

Thank you very much for the info.. it works for me..

7 Aaron October 20, 2010 at 4:00 am

i tried using kill(pid,0) to test whether the process is existent, need to include

Aaron

8 mohsin November 29, 2010 at 8:19 am

when i reconfigure (squid -k reconfigure) squid i got error.
like this
squid: ERROR: Could not send signal 1 to process 6471: (3) No such process
how i can remove this error please help me.

Thanks in advance

9 Pinoy June 4, 2011 at 5:12 pm

hanks ive been searching the net on how to find the pid of a process and this post solve my problem. thank you

10 Mikkel September 22, 2011 at 9:02 pm

Bear in mind that the command itself can show up in the results. For instance:

mikkel@www ~ $ ps aux | grep ntp
root     20417  0.0  0.0   4408  1316 ?        Ss   17:30   0:00 /usr/sbin/ntpd -p /var/run/ntpd.pid
mikkel   20429  0.0  0.0   2064   572 pts/0    S+   17:30   0:00 grep --colour=auto ntp

If you only see the grep command listed, that means the named command is not running.

11 Amensan November 6, 2011 at 5:27 pm

Hi,

I still can’t see my pid number for my postfix services. can’t find that. Help me. Thanks.

Using: Linux server 11.04

12 SALIM November 15, 2011 at 9:13 am

why ? mark indicating ?? while each ps -ef |grep some process

13 kamal March 14, 2012 at 6:53 am

Hii,
im facing one problem with pgrep command
I want to display the PID of process with greping on process name..im using this command for that:
pgrep -lfu $UID | grep -i AddUser | grep -v grep | grep bash | tr -s ” ” | cut -d ” ” -f1
but since the path of process AddUser is too long..the output of pgrep does not shows the fullname of process instead it crops the process name and displays only first 3 chars…Any idea to avoid cropping of process name

14 hari April 3, 2012 at 9:45 am