I have a script I'm working on in bash where after any input is given, after the input is processed, the whole thing is restarted using exec bash "${BASH_SOURCE}", waiting to process the next input given by the user. This all works as intended, save for one catch. I need to run an if statement, but only so it runs when the script is first run. I've tried a multitude of solutions, but can't figure anything out. Any suggestions are welcome

CodePudding user response：

I'm not sure what you're trying to do in the end, but repeated exec's seem like it might be best handled another way.

That being said, here's a solution that works:

#!/usr/bin/bash

if [ "$FIRST_RUN" = "" ] ; then
  FIRST_RUN=no
  export FIRST_RUN
  echo first run
fi

read ans
echo "answer: $ans"
exec bash "${BASH_SOURCE}"

CodePudding user response：

You can have the script pass an argument to itself indicating that it's already done the initialization (or whatever it is):

#!/bin/bash

if [[ "$1" != --init-done ]]; then
    # do initialization/first run stuff here
else
    shift # Remove the --init-done option
fi

...process input...

exec "$BASH_SOURCE" --init-done

If the script doesn't take arguments, you can skip the shift.