删除空行
g/^\s*$/d : delete all blank lines
这个里面使用了“:g”命令，Google了一下，找到了如下描述：
:g is something very old and which is very powerful. I just wanted to illustrate the use of it
with some examples. Hope, it will be useful for someone.
Brief explanation for ":g"
-------------------------
Syntax is:
:[range]:g/<pattern>/[cmd]
You can think the working as, for the range (default whole file), execute
the colon command(ex) "cmd" for the lines matching <pattern>. Also, for all
lines that matched the pattern, "." is set to that particular line (for
certain commands if line is not specified "." (current line) is assumed).
Some examples
-------------
Display context (5 lines) for all occurences of a pattern
:g/<pattern>/z#.5
:g/<pattern>/z#.5|echo "=========="
<< same as first, but with some beautification >>
Delete all lines matching a pattern
:g/<pattern>/d
Delete all blank lines (just an example for above)
:g/^\s*$/d
Double space the file
:g/^/pu =\"\n\"
:g/^/pu _
<< the above one also works >>
Copy all lines matching a pattern to end of file
:g/<pattern>/t$
Yank all lines matching a pattern to register 'a'
0"ay0:g/<pattern>/y A
Increment the number items from current line to end-of-document by one
:.,$g/^\d/exe "normal! \<c-a>"
Comment (C) lines containing "DEBUG" statements
g/^\s*DEBUG/exe "norm! I/* \<Esc>A */\<Esc>"
A Reverse lookup for records
(eg: An address book, with Name on start-of-line and fields after a space)
:g/<patern>?^\w?p "if only name is interested
:g/<patern>/ka|?^\w?p|'ap "if name and the lookup-line is interested
:g/<patern>/?^\w?|+,/^[^ ]/-1p "if entire record is interested
Reverse a file (just to show the power of 'g')
:g/^/m0
Foot note 1: use :v to negate the search pattern
Foot note 2: Some explanation of commonly used commands with :g
:2,8co15 => Copy lines 2 through 8 after line 15
:4,15t$ => Copy linesa 4 through 15 towards end of document (t == co)
:-t$ => Copy previous line to end of document
:m0 => Move current line to the top of the document
:.,+3m$-1 => Move current line through cur-line+3 to the last but one line
of the document
Foot note 3: Commands used with :g are ex commands, so a help search should
be,
:help :<help-topic>
eg. :help :k
尝试翻译如下
:g是一个非常老且很强的的命令。我只想通过一些例子来演示他的用法。希望对被人有用。
“:g”的概述
语法：:[rang]:g/<pattern>/[cmd]
你可以认为他是这么工作，在特定的范围内（[rang]确定，默认是整个文件）。他逐行逐行的用<pattern>去匹配，如果匹配成功就执行 冒号命令 （“cmd”来指定）。另外，如果<pattern>匹配所有行，那么只有对当前行执行 冒号命令。
今后会不断更新……
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:%s/^\(.*\)\n\1/\1$/ : 删除重复行 # 非贪婪匹配，\{-}
一会来分析