Re: scripting question: to parse data with varname=value pattern the easiest way?

[vogelke+debian@pobox.com (Karl Vogel)]

>> On Mon, 01 Nov 2010 15:49:01 +0800, 
>> Zhang Weiwu <zhangweiwu@realss.com> said:

Z> A program output is like this:
Z>   result_01: a="23" b="288" c="A_string" ac="34"
Z>   result_02: a="23" b="28" c="A_string_too" dc="3"
Z>   ....

Z> I am writing a script to output values of b if b is in the result set.

   If your data is trustworthy and follows shell assignment rules like the
   example above, you can abuse sh/ksh/bash:

     #!/bin/bash

     sample='result_01: a="23" b="288" c="A_string" ac="34"
     result_02: a="23" c="A_string_too" dc="3"
     result_03: a="23" b="28" c="A_string_too" dc="3"'

     echo "$sample" | while read str
     do
         unset b       # or whatever you're looking for
         set $str      # will fail horribly if $str is empty
         result=$1
         shift
         eval "$@"
         test "$b" && echo "$result $b"
     done
     exit 0

   On the other hand, if someone sneaks something like
       result_04: dc="3" rm /something/valuable

   into your program output, you'll get a nasty surprise.

-- 
Karl Vogel                      I don't speak for the USAF or my company

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