Re: some vi equivalents please?

[Kevin Rodgers <kevin.d.rodgers@gmail.com>]

Toby Cubitt wrote:
> rustom wrote:
>> 1. In vi I can delete a line that contains a <pat> with
>> :g/<pat>/d
>>
>> How is this done in emacs?
> 
>   M-x query-replace-regexp
> 
> then enter "^.*<pat>.*$" as the regexp (no quotes), and leave the
> replacement blank.
> 
> 
>> 2. match-variables:
>> If I want to remove everything after the second : (in a file that has
>> 3 fields separated with two :'s)
>> I do
>> :s/\(.*\):\(.*\):.*/\1 \2
>> How do I do that in emacs?
> 
>   M-x query-replace-regexp
> 
> then "^[^:]*\(.*\):\(.*\):.*$" for the regexp, and "\1 \2" for the
> replacement (again, no quotes).
> 
> The "^" and "$" both here and above are only there to prevent the regexp
> matching across lines (unlike sed, regexp searches in an Emacs buffer
> aren't line-oriented). Depending on your file, you might get away with
> something simpler. E.g. for 2, if you know there will always be two
> colons on every line, you could use "\(.*?\):\(.*?\):.*" instead ("?"
> makes a wildcard non-greedy).
> 
> query-replace-regexp is interactive, like query-replace. I find this
> useful just to check I've got the regexps right, and then hit "!" once
> I'm happy with it to replace all the rest non-interactively. The
> non-interactive version is replace-regexp.

Good advice!

> There are no doubt many other ways to accomplish this in Emacs...

Since rustom is used to vi's noninteractive way of using sed-like
commands:

C-M-h	; mark-whole-buffer
C-u M-| ; shell-command-on-region
sed '/<pat>/d'

C-M-h	; mark-whole-buffer
C-u M-| ; shell-command-on-region
sed 's/^\([^:]*\):\([^:]*\):.*$/\1 \2/'	; note the trailing /

-- 
Kevin Rodgers
Denver, Colorado, USA