Oops, I read that too late ...
Let's say my original lines are: CN=DATA.OU=XYZ.O=CO CN=DATA.OU=XYY.OU=MEM.O=CO CN=DATA.OU=XZZ.OU=OOP.O=CO
I want them to look like: CN=XYZ_DATA.OU=XYZ.O=CO CN=XYY_DATA.OU=XYY.OU=MEM.O=CO CN=XZZ_DATA.OU=XZZ.OU=OOP.O=CO
then the perl script would be
perl -pne 's/(CN=)(DATA.OU=)((.*?).O.*)$/$1$4_$2$3/' /file/name
Best regards,
Peter.