Re: [Help-bash] backgrounding a process sends it into a tailspin

[Cook, Rich]

Note that your gnuplot must have been compiled against readline for this to 
happen.  (It's the default option, but you never know)

On Sep 12, 2012, at 8:06 PM, Cook, Rich wrote:

> On Sep 12, 2012, at 7:17 PM, Chet Ramey wrote:
> 
>> On 9/7/12 8:46 PM, Cook, Rich wrote:
>>> Hello, 
>>> I have built and installed gnuplot and wrapped it in a bash script.  The 
>>> script simply makes a usage entry in a database, calls gnuplot, then notes 
>>> that it exits.  I'm including the script below.  
>>> 
>>> When the user runs this script and puts it into the background, gnuplot 
>>> immediately starts taking up 100% of a CPU, spinning in readline.  This 
>>> only happens when gnuplot is wrapped in this way, not when it's called 
>>> directly.  I would like to avoid this behavior, obviously, but I would also 
>>> like to continue using a wrapper script.  What is it about being called 
>>> from a script that is causing this odd behavior on gnuplot's part?  
>> 
>> I can't reproduce this on Mac OS X, using bash-3.2 to bash-4.2 and
>> gnuplot-4.whatever-fink-gives-you, or on Fedora 15, using bash-4.2 and
>> gnuplot-4.4.  I used the orignal script without the imgtrack stuff.
>> It doesn't matter whether I start the script in the background using `&'
>> or in the foreground and use ^Z.  Even ^Z/bg doesn't cause any weird
>> behavior.
>> 
>> Maybe we could get back to basics: system type, OS version, bash version,
>> gnuplot version.
> 
> OK, sure, great, thanks
> Here is some info: 
> address@hidden (lclocal.el6): uname -a
> Linux rzgpu2 2.6.32-220.23.1.1chaos.ch5.x86_64 #1 SMP Tue Jun 19 17:16:17 PDT 
> 2012 x86_64 x86_64 x86_64 GNU/Linux
> 
> chaos5 == rhel6 with some kernel mods, surely no changes to bash
> 
> address@hidden (lclocal.el6): bash --version
> GNU bash, version 4.1.2(1)-release (x86_64-redhat-linux-gnu)
> 
> address@hidden (lclocal.el6): gnuplot --version
> gnuplot 4.4 patchlevel 3
> 
> Also happens on gnuplot 4.6.0
> 
> 
>> Chet
>> 
>> -- 
>> ``The lyf so short, the craft so long to lerne.'' - Chaucer
>>               ``Ars longa, vita brevis'' - Hippocrates
>> Chet Ramey, ITS, CWRU    address@hidden    http://cnswww.cns.cwru.edu/~chet/
> 
> -- 
> ✐Richard Cook   
> ✇ Lawrence Livermore National Laboratory
> Bldg-453 Rm-4024, Mail Stop L-557        
> 7000 East Avenue,  Livermore, CA, 94550, USA
> ☎ (office) (925) 423-9605    
> ☎ (fax) (925) 423-6961
> ---
> Information Management & Graphics Grp., Services & Development Div., 
> Integrated Computing & Communications Dept.
> (opinions expressed herein are mine and not those of LLNL)
> 
> 
> 

-- 
✐Richard Cook   
✇ Lawrence Livermore National Laboratory
Bldg-453 Rm-4024, Mail Stop L-557        
7000 East Avenue,  Livermore, CA, 94550, USA
☎ (office) (925) 423-9605    
☎ (fax) (925) 423-6961
---
Information Management & Graphics Grp., Services & Development Div., Integrated 
Computing & Communications Dept.
(opinions expressed herein are mine and not those of LLNL)