Shebang is, in Unix slumng, the name given to the pair of characters #! found at the beginning of the executable programs interpreted. Sometimes it is called also hash-bang or sharpbang.
Following these characters complete the interpreter of the orders contained therein indicated route. Basically it is used to indicate that shell executes the commands contained in the following lines. Although many people think that you can run only shells, but also you can execute perl, awk, etc.
In the case of Oracle enviroments (also I have seen a lot in Sybase and MySQL on Linux) is often used #!/bin/ksh (korn Shell Which was developed by David Korn at Bell Labs in the early 1980s).
HTH – Antonio NAVARRO