It doesn't segfault on my system, but it uses an ugly system font; distinctly not courier. You need a space between the font name and the size.

-font=>"courier -12"
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You can string together lots of modifiers, you just need to space separate them.

-font=>"courier -12 bold italic"
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Did you want pixel sized fonts rather than point sized fonts? If the size argument is a positive number, it is interpreted as a size in points. If size is a negative number, its absolute value is interpreted as a size in pixels. If the font name has spaces in it You need to enclose it in curly brackets.

-font=>"{bitstream vera sans} 12 bold italic"
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