One of rare occasion that we have to reverse the whole file or part of the file content in line order. Vim handles such cases effortlessly.
This command given in below will reverse all lines in the current buffer:
:g/^/m0
- : start command-line mode.
- g means you’ll take an action on any lines where a regular expression matches
- / begins the regular expression (could have used any valid delimiter)
- ^ matches the start of a line (which matches all lines in the buffer)
- the second / ends the regular expression; the rest is an Ex command to execute on all matched lines (i.e. all lines in buffer)
- m means move (:help :move)
- 0 is the destination line (beginning of buffer)
This takes advantage of the implementation detail noted just below command, that :g works by first marking all lines that match, then visiting each mark in order to run the command. Hence, you first move the first line to the top, then the second above the first, then the third above the second, etc.
If you do not want to reverse the entire file, you can supply the range of lines to reverse to the command and adjust the destination accordingly. For example, to reverse only lines 100-150:
:100,150g/^/m99
If you are running Vim on a Unix-like operating system, the tac utility will reverse all lines for you. Like any external utility, you can call tac from Vim as an alternate method:
:%!tac
A range will also work with this method:
:100,150!tac
Either of these methods can easily be assigned a mapping or Ex command.
For example,
command! -bar -range=% Reverse <line1>,<line2>g/^/m0|nohl <br /> " REVERSE line ordering, and move those lines to the top of the file.
It is probably more useful to reverse the lines in-place, i.e. without moving them to the top:
command! -bar -range=% Reverse <line1>,<line2>g/^/m<line1>-1|nohl
You can refer to original content at Vim site.