in reply to Extract portion of string based on string separator

Here's a couple of generic functions which you can re-use for similar purposes later. 
sub path_parts(@) { shift=~m((/[^/]*))g }
sub limit_list($@) { $#_=-1+shift; @_ }

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You can use them for your current problem like this: 
my $orig_path = "/a/b/c/d/e/f";
my $trunc_path = join '', limit_list( 3, path_parts( $orig_path ) );

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