Thank you for your answers. In fact, i knew that with T or D, i could select or delete messages depending on the regex. But i have a lot of duplicate mails (because of feeds); regex change every time. Then, i would need a regex of regex. Precisely a bash script seems to be needed.
Thank you for help again. -- ---()()()----()()()----()()()--)()()(----)()()(----)()()(--- -()----()--()-()-----()----()--)(----)(-----)(-)(--)(----)(- ()----()----()()()----()()()----)()()(----)()()(----)(----)(