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

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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