I have a text file like this:
ge-0/0/45.0,First-Floor-Security,13
,Voice_First_Floor,18
ge-0/0/46.0,First-Floor-Security,13
,Voice_First_Floor,18
ge-0/0/47.0,AV-Media,155
,Building-Automation,75
,CobraNet,156
,First-Floor-Management,19
,First-Floor-Pavilion,11
,First-Floor-Security,13
,First-Floor-Users,10
,Guest-Wired,3
,Video,150
,Voice_First_Floor,18
,Wireless-Corp,410
,Wireless-Guest,420
,Wireless-Mtg,400
,Wireless-Voice,430
ge-1/0/0.0,First-Floor-Users,10
,Voice_First_Floor,18
I looking for a command to grab the first field of the line above and insert it into the line below. So for example, my resulting file would look like this:
ge-0/0/45.0,First-Floor-Security,13
ge-0/0/45.0,Voice_First_Floor,18
ge-0/0/46.0,First-Floor-Security,13
ge-0/0/46.0,Voice_First_Floor,18
ge-0/0/47.0,AV-Media,155
ge-0/0/47.0,Building-Automation,75
ge-0/0/47.0,CobraNet,156
ge-0/0/47.0,First-Floor-Management,19
ge-0/0/47.0,First-Floor-Pavilion,11
ge-0/0/47.0,First-Floor-Security,13
ge-0/0/47.0,First-Floor-Users,10
ge-0/0/47.0,Guest-Wired,3
ge-0/0/47.0,Video,150
ge-0/0/47.0,Voice_First_Floor,18
ge-0/0/47.0,Wireless-Corp,410
ge-0/0/47.0,Wireless-Guest,420
ge-0/0/47.0,Wireless-Mtg,400
ge-0/0/47.0,Wireless-Voice,430
ge-1/0/0.0,First-Floor-Users,10
ge-1/0/0.0,Voice_First_Floor,18
I have some understanding about grouping and backreferences but cannot seem to find a way to search, create a backreference, and then use that backreference in a different line. Is this possible? If so, would you please point me in the right direction?
Thanks,
Drew