Whenever we write a shell script the first statement would be #! /usr/bin/ksh or something of the same..

What does this signify??? I know # is a comment.. what is this ! for???

Give in your thoughts....


Thanks,
Nisha

It's to tell your shell what shell to you in executing the following statements in your shell script.

is that all hell666??????

Yes, that is it. But, this kind of comment should be in your first line of the script, only then does it take this form. Also, when your shell comes across this line, a new process is spawned and replaced with this shell of your choice, and it is this process which will parse your script.

On the first line of an interpreter script, the "#!", is the name of a program which should be used to interpret the contents of the file. For instance, if the first line contains "#! /bin/sh", then the contents of the file are executed as a shell script.

You can get away without this, but you shouldn't. All good scripts state the interpretor explicitly. The '!' is also known as intepreter for the script to recognise correct compiler to be used.