How to cut string and find missing pattern?

view full story

http://www.unix.com – i have list in file named sample.txt eg Quote: qm01121412 qm02121412 qm03121412 qm05121412 qm07121412 . . . qm24121412 i want to cut the 3rd and 4th character i.e. 01,02,03....,24(max length is 24) and i want to find the missing sequence .and display them i.e. Quote: seq qm04121412 and qm06121412 is missing in above series. (HowTos)