I create a .deb package for my app and postinst script is not running after installing . this is my postinst script under the the path of DEBIAN/myapp.postinst
#!/bin/sh
set -e
echo "start postinst packing"
#fix app process permission
sudo chown root:root /opt/MyApp/myapp
sudo chmod 4755 /opt/MyApp/myapp
echo "finish set permissions"
exit 0
in the DEBIAN/ directory create a file named postinst and copy your script into it, or change the name of myapp.postinst to postinst and you're ready to go