check if process is running in bash script - bash

Question

how can i check if a process is running, if it is running then echo "process is running" and keep them from using that process til its finished. i have this piece of code but i cant get it to not allow them to use that process after it echos:
#!/bin/bash
SERVICE=EXAMPLE
if ps ax | grep -v grep | grep -v grep | grep $SERVICE > /dev/null
then
echo -e ""
echo -e "${LIGHTRED}[!] ${WHITE}Please wait till process is finished."
fi

Answer 1

It seems you want to write a loop, not a single if statement.
And you probably want to sleep a bit between checking the condition.
#!/bin/bash
SERVICE=EXAMPLE
while ps ax | grep -v grep | grep "$SERVICE" > /dev/null
do
echo
echo -e "${LIGHTRED}[!] ${WHITE}Please wait till process is finished."
sleep 60
fi
The condition can be simpler if you have pgrep:
while pgrep "$SERVICE" >/dev/null
(Or the simpler while pgrep -q "$SERVICE" if your implementation of pgrep supports it.)
When there is no matching process (already finished or not started yet),
then the script will not produce any output.
If you want to get some output in that case,
then you can rework like this:
while true
do
if pgrep "$SERVICE" > /dev/null; then
echo
echo -e "${LIGHTRED}[!] ${WHITE}Please wait till process is finished."
sleep 60
else
echo "Process '$SERVICE' not running"
break
fi
fi
To print the message only once and just wait until the process is no longer running:
is_running() {
pgrep "$SERVICE" > /dev/null
}
if is_running; then
echo -e "${LIGHTRED}[!] ${WHITE}Please wait till process is finished."
while true; do
sleep 60
is_running || break
done
else
echo "Process '$SERVICE' not running"
fi

Answer 2

Another solution
#!/bin/bash
tput civis # hide cursor
until ! ps -ef | grep "$SERVICE" | grep -v "grep" > /dev/null; do
while ps -ef | grep "$SERVICE" | grep -v "grep" > /dev/null; do
echo -en "\r${LIGHTRED}[!] ${WHITE}Please wait till process is finished."
done
printf "\r%80s" "" # clear line
echo -en "\rProcess '$SERVICE' is completed!\n"
done
tput cnorm # show cursor again
This solution is useful also if you have multiple instance of the service together.