Wanted to modify a xml file, there were some scenarios I need to modify or delete lines based on regular expression for multiple lines. After tried for a while I almost believe I need create a python or shell script to do it. Then I found Global commands, really powerful. And with advanced substitute command, it can complete my requirement perfectly!

1. VERY MAGIC & NOMAGIC

1.1 very magic : search as regular

Vim’s regular expression syntax is more like POSIX. So when I need match a date like “2016-06-01”, the regular is

\d\{4\}-\d\{2\}-\d\{2\}/

Have to use quite many excape characters. After using VERY MAGIC

\v (lowercase): all the other charecters have special meaning except _, -, 0-9 and a-zA-Z

So using VERY MAGIC, it will be much more readable.

\v\d{4}-\d{2}-\d{2}

1.2 very nomagic : search as literal meaning

**\V (uppercase): ** all the characters has their literal meaning and must use \ for escape meanning.

2. Advance Subsitute

2.1 Special Character in Replace Field

The subsitute format is like:

:[range]s[ubstitute]/{pattern}/{replace-string}/{flags}

We can use following special characters in replace-string:

• \r is newline, \n is a null byte (0x00).
• \& is ampersand (& is the text that matches the search pattern).
• \0 inserts the text matched by the entire pattern
• \1 inserts the text of the first backreference. \2 inserts the second backreference, and so on.

2.2 Search with Capatured Group

Inorder to use \1 to \N, we need use () in search field to set matched text into groups.

Still using previous example, to match “2016-06-01”, the regular can be written as

\v(\d{4})-(\d{2})-(\d{2})

In this way, I can use \1 refer to 2016, \2 refer to 06 and \3 refer to 01.

2.3 Substitute Example

I want to change the date to datetime format in xml for all

<sch:sellThroughDate>2016-06-01</sch:sellThroughDate> 

The command could be:

:%s/sellThroughDate>\v\d{4}-\d{2}-\d{2}/\0T00:00:00/g

3. Global Command

The syntax is :

:[range]g/{pattern}/{cmd}

Gloabal act Ex command on multiple lines, that means you can almost do anything beyond your imagination.

3.1 Gloabal Delete

The easiest one I were using is delete lines based on a pattern

:g/{pattern}/d

We can also delete all the lines unmatch with:

:v[group]/{pattern}/d

3.2 Gloabal Sort

This is a command to sort element inside CSS, like :

html{
	margin: 0;
	padding: 0;
	border: 0;
	font-size: 100%;
	vertical-aligin: baseline;
}

You can run as:

:g/{/ .+1,/}/-1 sort