To test a value returned by a called function you can use the last status command directly after the function is called from your script. For example:
check_it_is_a_directory $FILENAME # this is the function call and check if [ $? = 0 ] # use the last status command now to test then echo "All is OK" else echo " Something went wrong!" fi
A much better way is to use an if statement when testing on either a return 0 or a return 1 value. Enclosing the function call with an if statement makes better logical reading. For example:
if check_it_is_a_directory $FILENAME; then echo "All is OK" # do something ?? else echo "Something went wrong !" # do something ?? fi
If the function is going to echo out ...