Re: base-files patch (atn: Eric Blake)

[Igor Pechtchanski <pechtcha at cs dot nyu dot edu>]

On Mon, 9 May 2005, Eric Blake wrote:

> According to John Morrison on 5/8/2005 1:52 AM:
> > On Fri, March 25, 2005 8:26 pm, Eric Blake said:
> >
> >>True enough.  And that points out another bug - echo "$0" may fail if $0
> >>starts with -, it should be echo -- "$0".  Isn't portable shell
> >>programming fun?
> >
> > Sorry that this has taken so long, but I'm just getting around to adding
> > all the fixes emailed wrt /etc/profile.  I tried the above, and it broke
> > so I checked the man pages,
>
> Serves me right for thinking that echo was standard when I typed my
> original message, rather than me actually testing at the command line.
> Yes indeed, POSIX requires that echo must interpret -- as a string
> operand, rather than the standard interpretation of being an argument
> separator.
>
> > so, I'm afraid that echo -- "${0}" won't work.
>
> This will work instead:
> case `printf %s "$0" | /usr/bin/tr '[:upper:]' '[:lower:]'` in
> bash | -bash | */bash )
> [..]

Or, of course, the standard "portable scripting" trick:

case "`echo "_$0" | /usr/bin/tr '[:upper:]' '[:lower:]'`" in
_bash | _-bash | _*/bash )
[..]

(or, if you don't mind a slightly longer command:
case "`echo "_$0" | /usr/bin/tr '[:upper:]' '[:lower:]' | /usr/bin/sed '/s/^_//'`" in
bash | -bash | */bash )
[..])
	Igor
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