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This is a gnuplot scripting question on unix like systems.
For shell executable gnuplot scripts starting like:-

#!/opt/local/bin/gnuplot

how do you switch to the gnuplot prompt in the starting terminal session, at the end of the script?

Adding load "/dev/stdin" at the end, switches the input, but gives no user prompt.

I would like to let the user replot their own data over the setup and background generated by the script, and/or enter other gnuplot commands. I am looking for an elegant solution within gnuplot. When using the #!/opt/local/bin/gnuplot -c in a gnuplot scriptfile (after a chmod +x), I would like ./script.gp to work the same way as call "script.gp" from gnuplot does. This is so we could subsequently replot "info.dat" at a gnuplot prompt in each case. I want to switch gnuplot from batch mode to interactive at the end of the script (probably like in the way a startup file would). I can't remember or find the command/trick for this (load "/dev/stdin" is close).

The plot window in this case is AquaTerm, gnuplot 5.0 patchlevel 3 (macports), and the terminal session is OS X "Terminal". --persist seems unhelpful in changing the experience.

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You want to send a load of plot commands from a file to gnuplot, then send a load of commands from your user's terminal, which suggests something like this:

{ cat plot.gp; while read cmd; do echo "$cmd"; done; } | gnuplot

Or if I flesh that out a bit:

{ cat plot.gp; while :; do >&2 echo -n "gnuplot> "; read -re c; [ "$c" == "quit" ] && break; echo "$c"; done; } | gnuplot

I am using this plot.gp

set xrange [-5:5]
plot sin(x),cos(x),x*x

That basic functionality can be spruced up quite a lot, if you feel fancy:

#!/bin/bash
gpfile=$1

{
   # Show user gnuplot version - on stderr because stdout is going to gnuplot
   gnuplot -e "show version" >&2

   # Strip shebang (but not comments) from plot commands and send to gnuplot
   grep -v "^#!" "$gpfile" 

   # Show plot commands from file to user - on stderr and prefixed with pseudo-prompt
   grep -v "^#!" "$gpfile" | sed 's/^/gnuplot> /' >&2

   # Read user input and forward onto gnuplot
   while :; do
      >&2 echo -n "gnuplot> "
      read -re c
      [ "$c" == "quit" ] && break
      echo "$c"
   done
} | gnuplot

enter image description here

You would save the above in a file called plotandinteract in your HOME directory, then make it executable (just once) with:

chmod +x $HOME/plotandinteract

Then you can run it with:

$HOME/plotandinteract SomePlotFile

There's probably a much more elegant solution with Tcl/expect but I can't work that out - looks like I need @GlennJackman again :-)

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2 Comments

I am impressed! However, I am looking for a solution within gnuplot which might work with shebang on unix and guplot>call "script.gp" on other systems.
The enhanced last version of my script works with scripts containg a shebang.

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