Re: Execute a Command in PS1 w/o Disturbing Previous Return Value?

[Aaron Davies <agdavi01@xxxxxxxxxxxxxx>]

On Friday, August 13, 2004, at 01:32 PM, Bart Schaefer wrote:

> On Thu, 12 Aug 2004, Aaron Davies wrote:
>
> > I'm trying to write a prompt that will do two things: include a file
> > frequently re-downloaded from the web, and indicate the return status 
> > of
> > the previous command. The problem is, if I cat out the file, it 
> > returns
> > 0, overwriting the return status read by the %(0?%) directive
>
> This should probably be considered a bug.

I dunno, I can see where someone might want a prompt so complicated it 
needed internal error-handling based on return value of executed 
commands (cat foo || cat bar, etc.). Would "fixing" this prevent that?

> > What can I do about this?
>
> In addition to Philippe's suggestion of using precmd so that $? is 
> saved
> and restored for you by the shell -- which is what should be happening
> during command substitutions in prompt expansion, but isn't -- a simple
> alternative is to use $(<...) instead of `cat ...`.
>
> You can also use $'...' instead of `echo '...'`
>
> export PS1='$(</tmp/temperature)'" %m%~ %(0?."\
> $'%{\e[1;32m%}:)%{\e[0m%}.%{\e[1;31m%}:(%{\e[0m%}'") %# "

Thank you, that works perfectly!
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