ls, cat, grep, head, tail, cut, |, echo, >, <, >>, sed
xdialog, gtkdialog
Look at (and modify) other people's code. Google to find it if necessary.
Find that recent topic about the reference card for linux commands. And the gtkdialog hints and tips thread.
Of course Puppy could always include a proper language like tcl as well
Do you know a good gtkdialog program? Please post a link here