From: Robert Klemme <bob.news@...>
Date: 2005-10-18T04:01:57+09:00
Subject: Re: starting a process after the previous one is done

Partha <tattvamasi@gmail.com> wrote:
> Corey,
> When I do so, it does the same thing
> I dont think ruby waits for the previous system command to be done
> before it runs the next line.
> ( They are concurrent?)

No way: sytem is synchronous, i.e. ruby will block until it has finished. 
Try it:

$ ruby -e 'system("sleep 10; echo 1");system("echo 2")'
1
2

> Ay other ideas of how I would be abel to wait on the previous process
> to run the next one?

If you see something different then maybe the processes you start are 
forking.  For some programs usually started as daemon there's a flag that 
prevents running in the background.  Maybe that can help you.

Other than that, if your programms fork themselfes you need to find a way to 
determine execution state and wait to that status change.

> Snippet shown below.

What exactly do you want to demonstrate with this?

> -rw-rw-r--   1 pvn      cad            0 Oct 17 10:27 1f_after
> -rw-rw-r--   1 pvn      cad        61261 Oct 17 10:27 1f
>
> pvngemini/home/pvn >cat t.rb
> #!/usr/local/bin/ruby -W
>
> print "Start\n"
> system("ls -lrt /home/pvn > 1f")
> system("touch 1f_after")

You can't really expect timestamps with differnt minutes, can you?  If you 
have GNU ls you can use option --full-time:

Robert@Babelfish2 /c/TEMP
$ touch 1 ; touch 2

Robert@Babelfish2 /c/TEMP
$ ls -t --full-time 1 2
-rw-r--r--  1 Robert Kein 0 2005-10-17 20:55:30.234375000 +0200 2
-rw-r--r--  1 Robert Kein 0 2005-10-17 20:55:30.140625000 +0200 1

Robert@Babelfish2 /c/TEMP

Kind regards

    robert