Hello sir,
we are able to do :
But when I goto /bin or /usr/bin to see the code of "ls". I found it to be encrypted. So can u please tell me how to encrypt a code in such a way that the user can run it but cannot see the source code.

example:
if I have a shell script named "sample.sh" as :
What is the command to encrypt it so that I can still execute it using 'bash' but cannot see the source code.
I tried using 'gpg' but it didnt work.Can u please tell me how

First off, 'ls' is not an "encrypted script", it's not a script at all -- it's programmed in C, which becomes machine language, which you potentially could understand if you were very determined. It's not encrypted, just obscure.

Second, 'chmod -r' will prevent the user from reading a file. Much better security than trying to obfuscate it, since that's all it would amount to -- after all, a file the user really can't decrypt is a file the machine really can't decrypt. But for the halibut, here's how I once embedded encryption in scripts. Without the password, they can't examine the source code or run it.

hello sir.
I did use the link u gave me.
there also we are still able to see the source code.
I want to know how to obfuscate a code so that the user can use it but cannot see the logic that I used....it must come in all "#&*!" symbols like the code that comes when we open "ls" from /bin or /usr/bin

I cant use "chmod -r" as the user can be root.He would change the permission and see the code.I dont want the root also to see that code.
How can I achieve it sir ?

Like I said, a file the user really can't decrypt is a file the machine really can't decrypt. To get something even root can't decrypt you'll need something out of root's hands, like the kernel or a hardware cryptoprocessor, to do the dirty work. Sadly this goes beyond my knowledge, but the TPM's in modern computers might be related to this.

Well, you could write something in C instead of shell. But that's not encrypted, just obfuscated, a determined user could still piece things together. And a system tracing program would be able to tell what system calls it made no matter what language it was written in.

why do you care if the root user can see your script??

I feel you have a bigger security problem if you NEED to hide script from the root user.