Shell Programming and Scripting

I read that whenever you provide wrong path at sha-bang it will generate an error with message "command not found", but when I run script with wrong path, it runs perfectly without generating any error. any reason ?

Code:

#!/home/usrname/etc
echo "hello"
exit 0

From a bash terminal, OSX 10.7.5...

Code:

Last login: Sun Nov 24 12:48:58 on ttys000
AMIGA:barrywalker~> #!/Users/barrywalker
AMIGA:barrywalker~> echo "Hello World."
Hello World.
AMIGA:barrywalker~> # Now from a script...
AMIGA:barrywalker~> chmod 755 shebang.sh
AMIGA:barrywalker~> ./shebang.sh
-bash: ./shebang.sh: /Users/barrywalker: bad interpreter: Permission denied
AMIGA:barrywalker~> _

Script used for second part...

Code:

#!/Users/barrywalker
echo "Hello World."
exit

It also depends where the "shebang" is in your script, and how you run the script.

As wisecracker demonstrated and scott mentioned, how you run the script is important. The shebang isn't used when the script is read by a shell on stdin or passed to a shell as a command line argument. The shebang is only relevant when the script is passed as an argument to execve(2).

In wisecracker's second example, execve(2) finds the "interpreter" but it's not a regular file. This sets errno to EACCES, i.e. "Permission denied".

Regards,
Alister

Ok thanks scott and alister, I've change my shebang to sha-bang .. it was just mistyped ...