APM: Next dumb Q: IF NULL????

[CaptNemo]

Why is it so hard to check for null values in perl!?!?!


Two situations:


1) checking is a variable is empty:

	IF ($product eq "")...
	IF ($product <> "")...
	IF ($product ne "")...
	IF ($product != "")...
	IF ($product eq NULL)...
	IF ($product <> NULL)...
	IF ($product ne NULL)...
	IF ($product != NULL)...


2) checking to see if command line args were present:

	IF ($ARGV[0] eq "")...
	IF ($ARGV[0] <> "")...
	IF ($ARGV[0] ne "")...
	IF ($ARGV[0] != "")...
	IF ($ARGV[0] eq NULL)...
	IF ($ARGV[0] <> NULL)...
	IF ($ARGV[0] ne NULL)...
	IF ($ARGV[0] != NULL)...

	...none seem to work.  HOW do you check for NULL values!?!?