Csdrhrt

I have the following sample:

1. TNT 00:00 2. Swing From The Gutters 7:34 3. Ten-Day Interval 13:29 4. I Set My Face To The Hillside 18:16 5. The Equator 24:26 6. A Simple Way To Go Faster Than Light That Does Not Work 28:27 7. The Suspension Bridge At Iguazu Falls 32:03 8. Four-Day Interval 37:42 9. In Sarah, Mencken, Christ And Beethoven There Were Women And Men 42:29 10. Almost Always Is Nearly Enough 50:01 11. Jetty 52:45 12. Everglade 1:01:09 1:05:32

Which I want to convert into:

1. TNT 00:00 

2. Swing From The Gutters 7:34 

3. Ten-Day Interval 13:29 

4. I Set My Face To The Hillside 18:16 

5. The Equator 24:26 

6. A Simple Way To Go Faster Than Light That Does Not Work 28:27 

7. The Suspension Bridge At Iguazu Falls 32:03 

8. Four-Day Interval 37:42 

9. In Sarah, Mencken, Christ And Beethoven There Were Women And Men 42:29 

10. Almost Always Is Nearly Enough 50:01 

11. Jetty 52:45 

12. Everglade 1:01:09 1:05:32

The logical path I was following is that I know there will always be a "dot" (.) that comes with the number of the track and I can use it as a guideline for the breaks. The trouble is, it has to crawl back one or two characters in order to keep the number of the tracks.

At least with GNU sed, you can insert a newline before all but the first matching sequence using a 2g modifier:

sed -E 's/[0-9]+./n&/2g' file

Just capture the number and the dot and insert a newline before them:

$ perl -pe 's/s(d+.)/n$1/g' file 

1. TNT 00:00 

2. Swing From The Gutters 7:34 

3. Ten-Day Interval 13:29 

4. I Set My Face To The Hillside 18:16 

5. The Equator 24:26 

6. A Simple Way To Go Faster Than Light That Does Not Work 28:27 

7. The Suspension Bridge At Iguazu Falls 32:03 

8. Four-Day Interval 37:42 

9. In Sarah, Mencken, Christ And Beethoven There Were Women And Men 42:29 

10. Almost Always Is Nearly Enough 50:01 

11. Jetty 52:45 

12. Everglade 1:01:09 1:05:32