Remove package identifier file during installation - macos

Question

I'm a newbie in OSx development.
I'm creating an installer package using Packagemaker 3.0.4. Since I want to remove the local settings of my app during installation, I decided to remove the com.identifier.plist. However, I'm not that good in scripting and I'm just starting to explore what Packagemaker is capable of.
Ideally, I want my implementation to be as simple as this:
Check if the .plist file exists
Remove it.
I have tried:
#!/bin/sh
defaults delete ~/Library/Preferences/com.identifier.AppName.plist
Then I saved the delete.sh file to the Desktop. I opened the Packagemaker app and provided the path to my Desktop: /Users/MyName/Desktop/delete.sh in the Scripts Postflight. Then I executed build & run. It didn't work. I thought that it might probably be the script, so I changed it to:
#!/bin/sh
rm ~/Library/Preferences/com.identifier.AppName.plist;
Then I loaded the delete.sh file the same way as I did on the script above. But I received this error:
Mar 29 20:50:54 Mac-mini installd[5425]: PackageKit: Install Failed: PKG: post-flight scripts for "com.testIdentifier.test.AppName.pkg"\nError Domain=PKInstallErrorDomain Code=112 UserInfo=0x100404220 "An error occurred while running scripts from the package “test.pkg”." {\n NSFilePath = "./postflight";\n NSLocalizedDescription = "An error occurred while running scripts from the package \U201ctest.pkg\U201d.";\n NSURL = "./Contents/Packages/test.pkg -- file://localhost/Users/MyName/Desktop/AppName.mpkg/";\n PKInstallPackageIdentifier = "com.testIdentifier.test.AppName.pkg";\n}
If anyone who has a Step-by-Step implementation of creating & adding script to the Packagemaker, and perhaps, my scripts aren't correct, it would be awesome if you could help me out.
Thank you so much in advance! :)

Answer 1

Did you try to launch your delete.sh from terminal? Looks like you have an error in syntax - ';' at the end of the rm command, and you should use -f flag for the rm command (see man rm) in other case script will prompt for confirmation and postflight script can't be interactive.
Edit: as 一二三 mentioned semicolon - is not the point, you should probably look to his answer. And before you'll create your package just try your script in terminal (you can do sudo su before to login as root)

Answer 2

I've got it...
Here's my script:
#!/usr/bin/env bash
file=~/Library/Preferences//com.identifier.AppName.plist
if [ -e "$file" ]
then
# file is found
/usr/bin/defaults delete ~/Library/Preferences//com.identifier.AppName
else
# file not found."
fi
exit 0
I then added it to PackageMaker. I'm not really sure if I'm right but I might have just forgotten to add the script's file into the contents. That's why it never worked earlier. I just put the script's path on the postflight.
Anyway, thanks a lot to everyone for the tips.