From: Robert Klemme <bob.news@...>
Date: 2005-11-03T22:12:08+09:00
Subject: Re: execeute gawk from inside ruby script

Hugh Sasse wrote:
> On Thu, 3 Nov 2005, Robert Gilaard wrote:
>
>> Dear folks,
>>
>> how can I execeute a awk (or any other script) from
>> within ruby?
>>
>> Currently I'm looking into the exec and fork part of
>> the kernel class but I'm not too sure I'm on the right
>> trach.
>
> That is a right track, but not the only one.
>>
>> The while loop in the script looks like this in test:
>>
>> while i<=202
>> location<< "#{i}"
>> exec "gawk -f fix_creacity.awk $location> defile.txt"
>>
>> i=i+1
>> location="snapshot"
>> end
>>
>> But in the ruby book I have seen that after the ruby
>> script doesn't get after the exec.
>
> Exec overlays the process with the new one. fork() duplicates the
> process then when the child execs you have two different ones.
> The parent then wait for the child process to die.
>>
>> But I want to repeat this a few times so what could I
>> do? Every time the while statement gets executed, I
>> would like a new output file.
>
> To save on the apparent complexities of fork and exec, look at
> system(), and look at
>
>   (0).upto(202) do |i|
>     %x{gawk -f fix_creacity.awk #{location}#{i}> defile.txt}
>   end
>
> For more fun look at open and what it says about "| ...", and for
> deeper exploration of this realm look at popen.

Pretty complete list.  I'd like to add "drop (g)awk and do it in Ruby" as
an option though. :-)

Kind regards

    robert