bash vs. ash vs. postinstall

[Igor Pechtchanski]

On Wed, 22 Jun 2005, Eric Blake wrote:

> According to Corinna Vinschen on 6/22/2005 7:27 AM:
> > What about something along these lines:
> >
> > - ash only provides /bin/ash.exe
> > - bash provides /bin/bash.exe and sh.exe (linked or copied)
> > - ash gets a dependency to bash.
> > - *Both* packages get postinstall #!/bin/bash scripts which copy bin/bash
> >   to /bin/sh.
> >
> > Would that help?
>
> I agree with the first three points.  But on the fourth one, does
> setup.exe really honor the #!?  (If it doesn't, then initscripts-0.9-1,
> squid-2.4.STABLE7-1, tcp_wrappers-7.6-1, and xinetd-2.3.9-1 currently have
> problems, because their postinstalls try to use #!/bin/bash.)

Setup runs postinstall scripts via "$SHELL -c $SCRIPT", which honors the
shebang.  The good news is that setup tries a few shells in order
(/bin/sh, /usr/bin/sh, /bin/bash, and /usr/bin/bash), so if /bin/sh is
missing, /bin/bash will be used.  The bad news is that "bash -c script"
will honor the shebang in the script, so if it has #!/bin/sh, bash will
attempt to execute /bin/sh (and fail with "bad interpreter" if it's
missing).

> All http://cygwin.com/setup.html says is that a postinstall.sh is run
> with the cygwin shell (so that should be cleaned up to be more exact).

See above.

> I don't think it would be too hard to provide a .bat that does the copy,
> though.

True, and it would be independent of whether /bin/sh is present.

> Also, I can see the value of ash having a postinstall script to copy
> bash to /bin/sh, but if bash is already providing /bin/sh in its
> package, does it really need the postinstall as well?

One other thing is that postinstall scripts are run in alphabetical order,
so naming the script 00bash.sh should make it execute first.
	Igor
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