Hi, I'm playing Crysis 1 and I'm trying to use the console to enter i_givesniperscope 1
but I keep getting the response "Warning: Unknown Command"

I've tried
i_givesniperscope 1
i givesniperscope 1
i_givesniperscope=1
i_givesniperscope = 1
i_givesniperscope_1

why isn't this working?