On Fri, Sep 25, 2009 at 10:08 PM, Jeff Squyres <jsquyres@cisco.com> wrote:

On Sep 24, 2009, at 12:46 PM, Mike Dubman wrote:

Im not familiar with :\n semantics, how does it force Bourne shell and what it actually does :)? (seems like leftovers from 1960....)

Yes, it might be left over from 1960. :-) But the nice thing is that you then don't have to identify /bin/sh or /usr/bin/sh. It's convenient and it works everywhere.

Found some info re ":\n" as a shebang line:
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':' was actually the first comment character.
All shells I tried still recognize it as such, so it is not obsolete, but perhaps slightly deprecated.

The first versions of csh used '#' as a comment and used the presence of one comment character or the other to decide which shell to run (assuming it was given a text file with the execute bit set). This was before the advent of the kernel-based #! "magic number"
The early "/bin/sh" versions assumed they were the only shell on the system and had no need to choose an interpreter.
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