what precisely does one need to know in perl to write a script or a test bench for a RTL code in verilog or vhdl..??

[Shah, Aalok S]

what precisely does one need to know in perl to write a script or a test bench for a 
RTL code in verilog or vhdl..??
 
also what is a perl script??? and how do u write one??
 
thanks
aalok