Shell script for running simultaneously two interfaces

Shell Programming and Scripting
1

Hi!

I have two environments on a machine and each one has some scripts for checking if some interfaces are down, and if so, it restarts them.

The issue now is that i cannot keep both interfaces running, on both environments i see the same process running.

How can i modify my scripts in order to reach that?

I have one script for checking if my .sh is running, and another one for restarting it (the first one calles the latter if it's down)

isRunning.sh is something like this:

ps -ef |grep -v grep |grep -v 'isProgRunning.sh'| grep -v 'stopProg.sh' |grep -v 'runProg.sh' |grep -v 'restartProg.sh'| grep -v 'ProgStopper' | grep 'XX:SurvivorRatio=4 -Xnoclassgc' >/dev/null 2>/dev/null

if [ $? -eq 0 ]
then
	echo ""
	echo "Process: " `ps -ef |grep -v grep |grep -v 'isProgRunning.sh'| grep -v 'stopProg.sh' |grep -v 'runProg.sh' |grep -v 'restartProg.sh'| grep -v 'ProgStopper' | grep 'XX:SurvivorRatio=4 -Xnoclassgc' | awk '{print $2}'`
	echo ""
	echo " is running"
	exit 0
else
	echo " is down"
	exit 1

fi

and the second sets a variable to hold the directory hierarchy from where it's executed, and it starts the interface, using nohup command.

what should i do?

2

I in such case use a different UID when having 2 instances of the same program running to differenciate them (different UID - same GID with group set as -rws-on the directories ...)

3

The traditional way to check if a process is running is PID files. When you start it, arrange for a file containing its PID to be created to reference later. This avoids the ps | awk | grep | sed | cut | kitchen | sink nonsense, and is a lot more portable, and allows you to run more than one of the same thing independently without them conflicting.

#!/bin/sh

# Often /var/run, but only root can write there
MYPIDFILE=/path/to/mypid.pid

if [ -f "$MYPIDFILE" ] && read -r PID "$PIDFILE" && ps "$PIDFILE" >/dev/null
then
          echo "Process is still running as PID $PID" >&2
          exit
fi

echo "Process is not running." >&2

# If your shell complains about 'disown', then your shell doesn't need it and it can be removed
/path/to/processtostart & disown # Assumes the process does not fork other PIDs

echo "$!" > "$MYPIDFILE"

echo "Now running as PID $!" >&2
exit

It's possible that your daemons are creating PID files somewhere already. Take a look around their files.

4

What you are saying is to set a variable with the pid of my process and check if it's running based on that pid?

Would that alone solve the problem of parallel processes or do i have to combine this solution with the change of uid?

More specificly, on each of the environments i have this binary folder i have different scripts for verifying the processes, i mean i run them from different paths, being different scripts. They have the same permissions now. Each pair of isProgRunning and runProg to be in the same gid, but have different uid?

5

No two programs will have the same PID while they're running.