/^$path(?=(\/[\S\/]*|$))/

It says, more or less: match the contents of $path, but only if followed by a slash (and optionally more slashes and non-space characters), or the end of the line. Here's my test program

#!/usr/bin/perl -w
 
my $path='/tmp/foo';
my @ex=('/tmp/foo', '/tmp/foo/', '/tmp/foo/bar', '/baz/tmp/foo/', '/tm
+p/food');
 
print join(" ", grep( /^$path(?=(\/[\w\/]*|$))/, @ex)), "\n";
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