Re: [Help-bash] A do nothing function

[Bob Proulx]

DJ Mills wrote:
> However, that raises the question of why you wouldn't ust omit the
> whole thing

Sometimes it is programmer efficiency.  I sometimes run into a case
like this snippet from a hook script in 'resolvconf'.  The reason
behind this isn't important here.  But I didn't want to restructure
the script.  I just wanted my modification to it.

  RSLVCNFFILES="$(/lib/resolvconf/list-records | sed -e '/^lo$/d' -e 
'/^lo[.]/d')"

I needed some special handling in a particular case.  So I modified it
like this:

  filter=cat
  if [ -f tun0.net ]; then
    filter="sed /^eth/d;/^wlan/d;/^NetworkManager/d"
  fi
  RSLVCNFFILES="$(/lib/resolvconf/list-records | $filter | sed -e '/^lo$/d' -e 
'/^lo[.]/d')"

Then the logic flows easily and the problem is solved with a minimum
chance of error creeping into it.  And it is easy to patch in the
future if the file is updated.  (And yes the resolvconf maintainer and
I have discussed the issue and we are both happy with situation.)

Or I might do something like this:

  case $fn in
  *.gz) cat=zcat ;;
  *) cat=cat ;;
  esac

And then use $cat just like I would use cat but based upon the
filename it will do the right thing.

Programmer productivity and easy of maintenance is usually more
important than absolute cpu efficiency.  Especially when you will
never be able to tell the difference.

Bob