what is this #!/bin/bash, I could not understand it, through cpp,
I suggest you take a look at this
wikipedia page: Shebang (Unix).
The "#!" announces the script can be executed and its contents will be passed to the executable given and interpreted.
C++ (cpp) is a compiled language. As #! is for interpreted files only (aka scripts), it is most likely you're not dealing with C++ but with a simple shell script.