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

[Bart Schaefer <schaefer@brasslantern.com>]

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.

> 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%}'") %# "