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This program is part of Netpbm.
pgmnoise creates a PGM image that is made up of pixels of random brightness.
You specify the dimensions of the image with the width and height arguments.
The randomness in the image is limited before Netpbm 10.37 (December 2006) -- if you run the program twice in the same second, you may get identical output.
In addition to the options common to all programs based on libnetpbm (most notably -quiet, see Common Options), pgmnoise recognizes the following command line options:
Default is 255.
This option was new in Netpbm 10.63 (June 2013).
Use this to ensure you get the same image on separate invocations.
By default, pgmnoise uses a seed derived from the time of day and process ID, which gives you fairly uncorrelated results in multiple invocations.
This option was new in Netpbm 10.45 (December 2008).