In reply to DK.

There is a variety of different shell script interpreters on Unix-like Operating Systems. This first line of the script (it is called "sha-bang line") tells the operating system which command interpreter should be used to interpret the script.
In particular, #!/bin/sh executes the script using the Bourne shell or a compatible shell, with path /bin/sh.

For more information, see About /bin/sh or (#!/bin/bash ) What exactly is this ?.