bash debug tips. semi OT

[ESGLinux]

Hello all,

thanks for your answers

the one I like much is the one proposed by Maarten. (it adds the mininum to
the code.)

Although the one proposed by Martijn is also good.


Thanks for your answers,

greetings

ESG


2009/5/4 Broekman, Maarten <Maarten.Broekman at fmr.com>

> You can just use the "alternate value" parameter expansion rule:
>
> $ export DEBUG=
> $ export DISPLAY=foo.bar.com:0.0
> $ echo ${DEBUG:+$DISPLAY}
>
> $ export DEBUG=1
> $ echo ${DEBUG:+$DISPLAY}
> foo.bar.com:0.0
> $
>
> Maarten Broekman
>
> >  -----Original Message-----
> >  From: redhat-list-bounces at redhat.com
> >  [mailto:redhat-list-bounces at redhat.com] On Behalf Of ESGLinux
> >  Sent: Monday, May 04, 2009 7:41 AM
> >  To: General Red Hat Linux discussion list
> >  Subject: Re: bash debug tips. semi OT
> >
> >  First tip for my question
> >
> >  reference:
> >  http://www.softpanorama.org/Scripting/Shellorama/bash_debugging.shtml
> >
> >  ### debecho (debug-echo), by Stefano Falsetto ###
> >  ### Will echo passed parameters only if DEBUG is set to a value. ###
> >  debecho () {
> >    if [ ! -z "$DEBUG" ]; then
> >       echo "$1" >&2
> >       #         ^^^ to stderr
> >    fi
> >  }
> >
> >  DEBUG=on
> >  Whatever=whatnot
> >  debecho $Whatever   # whatnot
> >
> >  DEBUG=
> >  Whatever=notwhat
> >  debecho $Whatever   # (Will not echo.)
> >
> >
> >  something better??? ;-)
> >
> >  ESG
> >
> >
> >  2009/5/4 ESGLinux <esggrupos at gmail.com>
> >
> >  > Hello all
> >  >
> >  > this is a question about debuging bash scripts. I think
> >  this is a semi off
> >  > topic because its not a red hat question ... but I´m sure
> >  all of us have an
> >  > answer to this question.
> >  >
> >  > I have several scripts  with echo commands to check variable values
> >  >
> >  > the code I use is like this
> >  >
> >  > if [ ! -z $DEBUG ]; then
> >  >     echo "variable: $variable"
> >  > fi
> >  >
> >  > thus If I set DEBUG=on I get a lot messages with the
> >  variable values.
> >  >
> >  > My question is if is there any tip to do this without
> >  using the if code
> >  > snipet (something like an inline function...)
> >  >
> >  > on the other hand any tip about debugging bash scripts is
> >  welcome (like
> >  > setting option flags -n, -v o -x)
> >  >
> >  > Greetings
> >  >
> >  > ESG
> >  >
> >  >
> >  >
> >  --
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> >
>
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