How to generate a number sequence in file using vi or Vim?

Question

Is there a way to generate a number sequence in vi or Vim?

For example, for an arbitrary range of lines i  through j (where i < j

Answer 1

Instead of a complicated construct you could simply use a macro with the CTRL-a function to increment a leading number. Example data:

aaa
bbb
ccc

first insert a start number and a space:

1 aaa
bbb
ccc

then record this macro on line 1 ( means press CTRL-a):

qq0yf 0j0P0q

Explanation:

1. qq: record macro into register q
2. 0: go to first column.
3. yf: yank all until and including the first space (remember your first line has 1 and a space).
4. 0jP: go down and paste the pattern at the start of the line.
5. 0: go to first column and increment number by one.
6. q: end macro recording.

this gives:

1 aaa
2 bbb
ccc

now you can apply this macro using @q as long as you want. If you need an increase of two just use CTRL-aCTRL-a instead of just once. Now you could apply this macro to consecutive lines, for example:

:.,$norm @q

will add leading line numbers for the rest of your file.