Notable bash $PATH behavior trivia

[Michael O'Donnell]

I just noticed that I was able to execute
programs in the current directory without
prefixing their names with ./ and without
having . in my $PATH.  After saying WTF?
a number of times I finally figured out that
it's related to my PATH being defined with
a leading colon, sorta like this:

   export PATH=:/bin:/usr/bin:/usr:local/bin

...so those of you who (for security reasons) are
careful to exclude "." from your $PATH need also
be careful about leading colons, apparently...