If you run ppm without any parameters on the command line, it should give you a command prompt of it's own , not a gui .
should give you something like this on screen :
Then you can use the commands listed in method 3 .
If ppm without paramaters gives you a gui instead of the interactive commandline prompt, you may have to start it with a special parameter to get the prompt.
Check the documentation for ppm on your system, it should have details about how to start ppm with the command prompt.