bash: loop through procces output and terminate the process

Question

I need some help with the following:

I use linux to script commands sent to a device. I need to submit a grep logcat command to the device and then iterate its output as it is being generated and look for a particular string. Once this string is found I want my script to move to the following command.

in pseudocode

for line in "adb shell logcat | grep TestProccess"
do 
    if "TestProccess test service stopped" in line:
       print line
       print "TestService finished \n"
       break
    else:
       print line
done

Answer 1

adb shell logcat | grep TestProcess | while read line
do
  echo "$line"
  if [ "$line" = "TestProces test service stopped" ]
  then echo "TestService finished"
       break
  fi
done

Answer 2

adb shell logcat | grep -Fqm 1 "TestProcess test service stopped" && echo "Test Service finished"

The grep flags:

1. -F - treat the string literally, not as a regular expression
2. -q - don't print anything to standard output
3. -m 1 - stop after the first match

The command after && only executes if grep finds a match. As long as you "know" grep will eventually match and want to unconditionally continue once it returns, just leave off the && ...

Answer 3

You could use an until loop.

adb shell logcat | grep TestProccess | until read line && [[ "$line" =~ "TestProccess test service stopped" ]]; do
 echo $line;
done && echo -n "$line\nTestService finished"