Gfrktyl

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

Here's a command you could use:

:g/^,/norm 0kyt,jP

This uses the "global" command. Here's what it basically does:

:g/<regex>/<command>

will run "command" on every single line that matches the "regex". Our regex is pretty simple: Any line that starts with (^) a comma (,).

The command:

norm 0kyt,jP

norm means "run these characters like I typed them in normal mode". So 0k goes to the beginning of the last line with a comma. yt, is yank until ,. jP goes back to the line we matched on and pastes from the clipboard before the comma.

Conveniently, this runs each line in order, so it works on multiple entryless lines in a row, such as

,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

This is because on the "building automation" line, it will grab the "ge-0/0/47.0" from the previous line, and then paste it on this line. Then, on the "cobraNet" line, it will grab the new "ge-0/0/47.0" from the "building automation" line, etc.