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Question

I want to do something similar to this question: https://stackoverflow.com/q/11092608/855050.

I want to plot simultaneously all the files in a directory, without having to explicitly write their names. The column numbers are the same for all the files. What can I do?

Doing plot for [file in *] file u 3:2 doesn't work.

Also, I don't want each file to have a different legend. All points from all files should be treated the same, as if they all came from a single file.

Answer

You could try something like:

a=system('a=`tempfile`;cat *.dat > $a;echo "$a"')
plot a u 3:2

This uses the command line tempfile command to create a safe, unique, and disposable temporary file. It mashes all of the data files into this file. It then echoes the file's name so gnuplot can retrieve it. Gnuplot then plots things.

Worried about header lines? Try this:

a=system('a=`tempfile`;cat *.dat | grep "^\s*[0-9]" > $a;echo "$a"')

The regular expression ^\s*[0-9] will match all lines which begin with any amount of whitespace followed by a number.