$ perl -Mre=debug -le " $_ = q[ro/sham/bo]; print m{/(.+?)$} "
Compiling REx "/(.+?)$"
Final program:
   1: EXACT </> (3)
   3: OPEN1 (5)
   5:   MINMOD (6)
   6:   PLUS (8)
   7:     REG_ANY (0)
   8: CLOSE1 (10)
  10: EOL (11)
  11: END (0)
anchored "/" at 0 floating ""$ at 2..2147483647 (checking anchored) minlen 2
Guessing start of match in sv for REx "/(.+?)$" against "ro/sham/bo"
Found anchored substr "/" at offset 2...
Found floating substr ""$ at offset 10...
Starting position does not contradict /^/m...
Guessed: match at offset 2
Matching REx "/(.+?)$" against "/sham/bo"
   2 <ro> </sham/bo>         |  1:EXACT </>(3)
   3 <ro/> <sham/bo>         |  3:OPEN1(5)
   3 <ro/> <sham/bo>         |  5:MINMOD(6)
   3 <ro/> <sham/bo>         |  6:PLUS(8)
                                  REG_ANY can match 1 times out of 1...
   4 <ro/s> <ham/bo>         |  8:  CLOSE1(10)
   4 <ro/s> <ham/bo>         | 10:  EOL(11)
                                    failed...
                                  REG_ANY can match 1 times out of 1...
   5 <ro/sh> <am/bo>         |  8:  CLOSE1(10)
   5 <ro/sh> <am/bo>         | 10:  EOL(11)
                                    failed...
                                  REG_ANY can match 1 times out of 1...
   6 <ro/sha> <m/bo>         |  8:  CLOSE1(10)
   6 <ro/sha> <m/bo>         | 10:  EOL(11)
                                    failed...
                                  REG_ANY can match 1 times out of 1...
   7 <ro/sham> </bo>         |  8:  CLOSE1(10)
   7 <ro/sham> </bo>         | 10:  EOL(11)
                                    failed...
                                  REG_ANY can match 1 times out of 1...
   8 <ro/sham/> <bo>         |  8:  CLOSE1(10)
   8 <ro/sham/> <bo>         | 10:  EOL(11)
                                    failed...
                                  REG_ANY can match 1 times out of 1...
   9 <ro/sham/b> <o>         |  8:  CLOSE1(10)
   9 <ro/sham/b> <o>         | 10:  EOL(11)
                                    failed...
                                  REG_ANY can match 1 times out of 1...
  10 <ro/sham/bo> <>         |  8:  CLOSE1(10)
  10 <ro/sham/bo> <>         | 10:  EOL(11)
  10 <ro/sham/bo> <>         | 11:  END(0)
Match successful!
sham/bo
Freeing REx: "/(.+?)$"