Differences .app and .pkg implementations

From my research and general inquisitiveness, I've attained a satisfactory level of knowledge about Mac hardware and OS X, without ever having owned a single Apple product. I consider my position on the the raging "Mac vs PC" issue to be "indifferent". I do use Windows-based platforms, but I am seriously interested in investing in a Mac in the near future.

That being said, the first notable feature I noticed in OS X is the package-based way of installing applications. It's so delightful to have an entire application system nicely encapsulated in a convenient .app file. To install, copy the app file to the system, to delete, just delete the .app file. That's very simple, of course not taking in account left over plist files, and other whatnot.

My experience with .pkg installers is a different story, however. What I want to know is, what actually happens when installing an application the more "traditional" way with a .pkg file? My experience is that I have little or no control over where the pkg installs the application; I can only choose which drive it goes in. I get suspicious; what else happens in this "installation" process? Are a bunch of potentially wicked or destructive scripts or commands executed which could possibly alter the operating system? Can secret directories be created in various random places? I would like to obtain any technical information about the actual limitations of a pkg installer and what damage it could do if allowed. Am I correct that I have to run an uninstaller to delete a .pkg-installed application? Or is it safe to delete these kind of programs by the normal operation of dragging them to the trash?

Thank you very much for any information.

 

pkg installers are designed a specific way from the maker... you do not have options unless they give them to you. They can do anything... so yes you have to be careful, and trust the sources you get things from.

Wether its safe to delete or needs an uninstaller depends on the installer and how it was made and what it does... some you do, some you don't.

 

All right, I was afraid of that.

Thanks for the information.

 

Sorry if this is a dumb question... but what exactly does it mean if I have an app crossed out in the app folder... like a circle with a slash through it

I tried dragging the TransmissionBT app into my app folder but it has that cross mark over it

 

just means there is something wrong with it... some of the files inside could be missing... or anything else.

 

Mine does that when I download files and drag an app into the folder. It reminds me that I downloaded something from the internet and should only trust it if I know that it's from a trusted source, yadda yadda yadda. The icon goes back to normal once I run it once. That might be what it is.

 

Also, Stuff like packages would be what COULD contain a virus or a keylogger, So if it asks for your password and you think it shouldn't or it's not from a trusted source, be careful.