What does #!/bin/sh at the beginning of a file do?

[Gary Cooper_1]

Am I right in thinking that:

#!/bin/sh
or
#!/bin/ksh

makes sure the script is run using the shell referenced in the first line? I.e. if the user is using ksh, it will over-ride ksh and execute the script as a sh script (or vice-versa).

Thanks,

Gary Cooper

[Stefan Farrelly · Accepted solution]

ys, it confirms which shell to run the script under when executed.

[U.SivaKumar_2]

Hi,

#! is a magic macro which at the beginning of a shell script will make the shell script executed by the specified shell.

eg:-

#!/bin/ksh
ls

the above shell script will use ksh shell to run ls command.

regards,
U.SivaKumar

[Gary Cooper_1]

Thanks guys for such a phenomenally rapid response - 5 minutes, wow!

The HP ITRC user forum really is great!

Regards,

Gary

[H.Merijn Brand (procura]

To be more correct, it does not have to be a shell. It can be any interpreter. Most of them will even take command line options in the `hashbang' line as it is called.

#!/usr/bin/perl -w

#!/usr/bin/sh

#!/usr/bin/awk

#!/home/user/scripts/myscript -x -duh

etc

Enjoy, have FUN! H.Merijn

[Frank Slootweg]

In case you wonder where this is documented: In the exec(2) ("man 2 exec") manual page. Just search the page on "#!".

[A. Clay Stephenson]

And lastly, it's pronounced
'shebang' so if you ever hear someone say it, it doesn't mean magic. Magic is altogether different and we have "magic numbers" and "magic cookies" and no I am not pulling your leg.

[Gary Cooper_1]

And I thought Ricky Martin was singing about the wayward antics of some woman - I never guessed he was a Unix SysAdmin!

Cheers,

Gary

[W.C. Epperson]

And from the old grey haired systems weenie....

It was orignally called "hashpling". See:
http://www.uni-ulm.de/~s_smasch/various/shebang/