If you work with numbers you may find useful xxplot.
You can obtain it by:

$ ftp tiger.vscht.cz
Name: ftp
331 Guest login ok, send ident as password.
Password:
ftp> cd pub/xpplot
ftp> bin
ftp> get xpplot.tar.gz
ftp> quit
$ gunzip xpplot.tar.gz
$ tar xf xpplot.tar
$ cd xpplot
$ cc -o xpplot xpplot.c -lm -lX11
$ cp xpplot.1 /usr/local/man/man1

And then try 

$ xpplot -h
$ xpplot -H 
$ xpplot d
$ xpplot x y 
$ xpplot < xy
$ man xpplot

Pavel POKORNY                    Department of Mathematics
phone: +42 2 2435 5033           Prague Institute of Chemical Technology
fax:   +42 2 311 7335            Technicka 5
e-mail: Pavel.Pokorny@vscht.cz   166 28 PRAGUE
                                 Czech Republic
