About Platypus
Platypus is a Mac OS X developer tool that creates application wrappers around scripts. This means that your interpreted scripts can be launched from the Mac OS X window environment — e.g. the Finder or the Dock — without requiring use of the command line interface. They effectively become regular Mac OS X applications.
Platypus was first conceived in 2003 and implemented using the Carbon APIs. It has since gone through over two dozen major updates, and is now entirely written in Objective C for the Cocoa APIs.
Platypus is free, open-source software distributed under the terms and conditions of the Free Software Foundation’s GNU General Public License. This means the source code is freely available and you are free to modify and distribute it as you see fit, as long as it remains open.
Reference: http://www.sveinbjorn.org/files/manpages/PlatypusDocumentation.html#71
Notes
There are several ways to convert shell scripts into applications. Platypus offers the most customization and options in a GUI, Appify is the quickest way to create one from the command line, and SetFile is a good solution for your own personal use (not intending to distribute).
When using Platypus, you don’t need sudo.
For example,
sudo installer -pkg “install.pkg” -target “/”
becomes
installer -pkg “install.pkg” -target “/”
or…if you have issues, try ./install.pkg -target /