如何检查进程是否在Linux中运行

Question

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?

Answer 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, eg 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, eg 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.

Answer 2

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

Answer 3

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

Answer 4

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

Answer 5

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

Answer 6

On my system, ps aux | grep ProcessName 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.

Answer 7

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

Answer 8

返回0表示成功，而其他失败

kill -0 `pid`; echo $?

Answer 9

尝试这个

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