Source Data:
/foo/bar/xzy
/foo/bar/xzy/asdf
/foo/bar/xasdf
/bar/foo/asdf
/bar/asdf/foo

- Control string all positive in the beginning (must now the length of the lognest string)
- Control string can only switch from 1 to 0 not from 0 to 1

Setp 0 - Initiliaze Control String
Control: 11111111111111111
Step 1 - compare line 1 and 1+1
Line 1:  /foo/bar/xzy
Line 2:  /foo/bar/xzy/asdf
Control: 11111111111100000

Step 2 - compare line 2 and 2+1
Line 2:  /foo/bar/xzy/asdf
Line 3:  /foo/bar/xasdf
Control: 11111111110000000

Setp 3
Line 3:  /foo/bar/xasdf
Line 4:  /bar/foo/asdf
Control: 10001000100000000

Step4
Line 4:  /bar/foo/asdf
Line 5:  /bar/asdf/foo
Control: 10000000000000000

Step5: Count how many 1 are in the control string, beginning from left, breaking at first 0
Step6: remove that many characters from the beginning of each source string.