bash scripting across linux and solaris

[me-5yx05kfkO/aqeI1yJSURBw at public.gmane.org (Matthew Gillen)]

On 08/26/2009 05:49 PM, David Rosenstrauch wrote:
> On 08/26/2009 05:45 PM, Stephen Adler wrote:
>> Hi all,
>>
>> I'm writing a bash script which I would like to execute the same script 
>> on a linux and a solaris system. but my problem is that the bash 
>> executable is in /usr on linux and /usr/bin on solaris. So how do I 
>> define the first line #! syntax so that the shell which is executing the 
>> script knows where to pick up the executable.
> 
> Can't you just use:
> 
> #!/bin/sh

No, because that shell hasn't been bourne again! :-P
Strictly speaking, 'bash' is a superset of 'sh'.  Some linux systems make
'sh' a symlink to 'bash', but not all (ubuntu IIRC is one that doesn't), and
solaris certainly doesn't.

This matters since a linux distro like fedora that just uses bash for sh
will not enforce 'sh-only' syntax, whereas ubuntu and solaris, which use
actual 'sh' binaries, will.

>From the school of hard knocks: unless you're an expert 'sh' programmer,
don't develop scripts that start with #!/bin/sh on fedora and the like,
since you can't be sure they'll work on systems that actually use the shell
you're telling it to use.

Matt