I want to split it at the first single '\'

Well you can split on the first '\' and you can use the 3rd argument of split to get 2 separate strings, but it won't do quite what you want, as you'll lose the '\'. If you want to split in the middle of a string then it'll be easier just to match it

my $str =
    q[\\\\Srvbuild\e\ADW61\VENDOR\MICROSOFT\PLATFORMSDK\INCLUDE];
my($network, $path) = $str =~ m<^ ( (?:\\+ \w+){2} )(.*)>x;
print "network - $network", $/, "path - $path", $/;

__output__

network - \\Srvbuild\e
path - \ADW61\VENDOR\MICROSOFT\PLATFORMSDK\INCLUDE
[download]

HTH

_________
broquaint