CODEWITHSUNDEEP
linuxbash
noMAD
noMAD

Reputation: 7844

How to check if process is running in linux

I am trying to automatically check if a process is running or not and have to perform next steps accordingly. I had written a bash script but it doesn't seem to work.

if ps aux | grep [M]yProcessName > /dev/null
then
  echo "Running"
else
  echo "Not running"
fi

Is my if statement wrongly used?

Upvotes: 16

Views: 69493

Answers (10)

6equj5
6equj5

Reputation: 111

Just to explicitly mention a way this answer alluded to, pgrep is the best way to do this by process name:

pgrep [M]yProcessName

If a process whose name matches "[M]yProcessName" is running, pgrep will print its PID to stdout and will exit with code 0. Otherwise, it will print nothing and exit with code 1.

Upvotes: 1

ssaa
ssaa

Reputation: 1112

ps aux | grep [M]yProcessName | grep -v grep

Upvotes: 9

vinllen
vinllen

Reputation: 1459

return 0 means success while others failed

kill -0 `pid`; echo $?

Upvotes: 1

Ender Fletcher
Ender Fletcher

Reputation: 53

SMBD=$(pidof smbd)
if [ "$SMBD" == "" ];
then
   /etc/init.d/samba start;
else
   /etc/init.d/samba restart;
fi

Upvotes: 1

Yogeesh Seralathan
Yogeesh Seralathan

Reputation: 1414

processid =$(ps aux | grep 'ProcessName' | grep -v grep| awk '{print $2}')

The above command will give you the process id. Assign that process id to a variable and do this -->

if cat /proc/$processid/status | grep "State:  R (running)" > /dev/null
then
  echo "Running"
else
  echo "Not running"
fi

Upvotes: 2

Guest67
Guest67

Reputation: 43

There is a solution:

if [ "$(ps aux | grep "what you need" | awk '{print $11}')" == "grep" ]; then ... elif [ ... ]; then ... else ... fi

This works fine in Debian 6. '{print $11}' is needed, because the sytem treats grep as a process as well

Upvotes: 2

Edw4rd
Edw4rd

Reputation: 79

On my system, ps aux | grep ProcessName always get a line of that grep process like:

edw4rd     9653  0.0  0.0   4388   832 pts/1    S+   21:09   0:00 grep --color=auto ProcessName

So, the exit status is always 0. Maybe that's why your script doesn't work.

Upvotes: 0

Basile Starynkevitch
Basile Starynkevitch

Reputation: 1

You don't want to know if a particular process (of known pid) is running (this can be done by testing if /proc/1234/ exists for pid 1234) but if some process is running a given command (or a given executable).

Notice that the kill(2) syscall can be portably used to check if a given process is running (with a 0 signal, e.g. kill(pid,0)). From inside a program, this is a common way to check that a process of known pid is still existing and running (or waiting).

You could use the pidof command to find the processes running some executable, e.g. pidof zsh to find all the zsh processes. You could also use killall -s 0 zsh

And you might be interested by the pgrep utility and the /proc filesystem.

Upvotes: 12

gaoxinbo
gaoxinbo

Reputation: 164

try this

ps aux | grep [M]yProcessName | grep -v grep

Upvotes: -1

Joe Yang
Joe Yang

Reputation: 23

Using -z to check if a string is empty or not, something like this could work:

line=$(ps aux | grep [M]yProcessName)
if [ -z "$line" ]
then
    echo "Not Running"
else
    echo $line > /dev/null
    echo "Rinnung"
fi

Upvotes: 2

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