Re: command line

[Dave D. <dde...@es...>]

Dhiman Barman <dh...@ca...> writes:

> hi,
>   mean, it will be useful to have support for loops, variable 
>   assignment in gnuplot files. 
>   
>   if I have to plot 100 files where only the output filename 
>   and input file name change, it will be useful to have loop
>   support...but that also means having compiler/interpreter
>   support. 
>

>> On Wednesday 30 August 2006 05:19 pm, Dhiman Barman wrote:
>> >   Is there any option of taking input from command
>> > line options while running gnuplot file.gnu?
>> 


There is a trick I once came up with, but for which I've never really
found a good use for. Maybe this is it...

Assuming unix :

$ gnuplot 3< /tmp/somefile

runs gnuplot with file 3 reading from /tmp/somefile

Then inside your script, you can shell-out to read lines from that file
descriptor.

$ cat /tmp/somefile
hello
world

$ gnuplot 3< /tmp/somefile
        G N U P L O T
        Version 4.0 patchlevel 0
        last modified Thu Apr 15 14:44:22 CEST 2004
        System: Linux 2.6.8-2-686-smp
...

gnuplot> print "`head -1 <&3`"
hello
gnuplot> print "`read x <&3 ; echo X $x Y`"            
X world Y

You just need to be careful that a shell-ed out process doesn't read
more from the file than you wanted it to.


dd
-- 
Dave Denholm              <dde...@es...>       http://www.esmertec.com