Gnuplotting gzipped files

Question

I would like to use a command like

plot 'datafile.gz' u 1:2

in gnuplot for a data file that is gzipped. Of course gnuplot does see that the file is gzipped and unzip it for me. Is there a way to have gnuplot handle a gzipped file directly without me having to unzip it to disk first?

Answer 1

Yes:

gzcat datafile.gz | plot '-' u 1:2

Answer 2

If you feed gnuplot its commands from the unix command line, you can also pipe data to it from another program, like zcat which reads in a gzipped file and prints it out, e.g.:

zcat datafile.gz | gnuplot -p -e 'plot "-" u 1:2'

EDIT:

Apparently, in place of a filename, you can give gnuplot's plot command a shell command to run and use the output of. Just put a < in front:

plot "< zcat datafile.gz" u 1:2

You should be able to use that multiple times to do what you want.

(Answer courtesy of philipp.janert on the 'Gnuplot in Action' forum http://www.manning-sandbox.com/message.jspa?messageID=77092)