IT-Common executable file extensions
.scexe
Self-extracting firmware updates that Hewlett-Packard (HP) produces, commonly associated with Linux machine.
.bat
Batch file. Use to execute multiple commands from the windows command prompt( cmd .exe) within one file.
.app
Excites a program within OS X (as .exe does in Windows.
.msi
For installation and removal of software within windows. Opening an .msi file actually launches msiexec .exe which read the .msi file and does what it says. .msi files use windows installer, so think of it as standing for "Microsoft installation".
.exe
short for "Executable", it tells the OS to run the program. Most windows desktop programs use this extension.