There are two ways to specify the rectangle to cut: arguments and options. Options are easier to remember and read, more expressive, and allow you to use defaults. Arguments were the only way available before July 2000.

If you use both options and arguments, the two specifications get mixed in an unspecified way.

To use options, just code any mixture of the -left, -right, -top, -bottom, -width, and -height options. What you don't specify defaults. It is an error to overspecify, i.e. to specify all three of -left, -right, and -width or -top, -bottom, and -height.

To use arguments, specify all four of the left, right, width, and height arguments. left and top have the same effect as specifying them as the argument of a -left or -top option, respectively. width and height have the same effect as specifying them as the argument of a -width or -height option, respectively, where they are positive. Where they are not positive, they have the same effect as specifying one less than the value as the argument to a -right or -bottom option, respectively. (E.g. width = 0 makes the cut go all the way to the right edge). Before July 2000, negative numbers were not allowed for width and height.

Input is from Standard Input if you don't specify the input file pnmfile.

Output is to Standard Output.

If you are splitting a single image into multiple same-size images, pamdice is faster than running pamcut multiple times.