$path='./anything/../.../something'; #example
$path=~s!/+!/!g; #replace //// by single /
$path=~s!^\./!!; #remove starting ./
$path=~s!/\.(?=$|/)!!g;  #remove all /.
1 while $path =~  s!/([^/]{3,}|[^/.][^/]*|\.[^/.])/\.\.(?=/|$)!!g; #remove  /something/..
$path=~s!^([^/]{3,}|[^/.][^/]*|\.[^/.])/\.\./!!;  #remove starting something/../
$path='.' if $path eq ''; #point current path if finally it is empty
#at this place $path is normalized