linux下sed的使用(下)
本篇主要讲解：
---sed的导入和导出
sed数据的导入和导出（是一种非交互式的导入和导出，可用在脚本中）
r 导入 （把其他文件的内容放到当前文件里）
w 导出 (文件另存为)
Sed导入格式
sed -i ‘定址符r 文件A’ 文件B
把文件A的数据导入到 文件B里
导入的时候是逐行导入的，B文件必须事先存在，且最少有一行，一行都没有的情况下是导入不了的
–默认会逐行导入
–使用定址符限制输入数据的位置
–定址符可以使用行号、正则表达式表示
Sed导出格式
sed -i ‘定址符w 文件A’ 文件B
把文件B的数据导出到 文件A里（另存为）
–覆盖导出
–文件A不用事先创建
–若文件A事先存在 会覆盖其内的数据
一、
1．sed导入导出的基本用法
1）r 读入其他文件内容。
以前面的rclocal.txt文件为例，确认文件内容：
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[root@svr5 ~]# cat rclocal.txt
1 #!/bin/sh
2 #
3 # This script will be executed *after* all the other init scripts.
.4 # You can put your own initialization stuff in here if you don't
5 # want to do the full Sys V style init stuff.
67 touch /var/lock/subsys/local
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读入/etc/sysconfig/network文件的全部内容，插入到rclocal.txt文件的第5行之后（注意：需加-i才真的保存，否则只输出结果）：
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[root@svr5 ~]# sed '5r /etc/sysconfig/network' rclocal.txt
1 #!/bin/sh
2 #
3 # This script will be executed *after* all the other init scripts.
4 # You can put your own initialization stuff in here if you don't
5 # want to do the full Sys V style init stuff.
NETWORKING=yes
NETWORKING_IPV6=noHOSTNAME=svr5.tarena.com67 touch /var/lock/subsys/local
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在rclocal.txt文件的每一行下方都插入/etc/sysconfig/network文件的内容：
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[root@svr5 ~]# sed 'r /etc/sysconfig/network' rclocal.txt
1 #!/bin/sh
NETWORKING=yes
NETWORKING_IPV6=noHOSTNAME=svr5.tarena.com2 #
NETWORKING=yes
NETWORKING_IPV6=noHOSTNAME=svr5.tarena.com3 # This script will be executed *after* all the other init scripts.
NETWORKING=yes
NETWORKING_IPV6=noHOSTNAME=svr5.tarena.com.. .. |
2）w 将过滤结果保存到指定的文件。
以前面的rclocal.txt文件为例，确认文件内容：
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[root@svr5 ~]# cat rclocal.txt
1 #!/bin/sh
2 #
3 # This script will be executed *after* all the other init scripts.
4 # You can put your own initialization stuff in here if you don't
5 # want to do the full Sys V style init stuff.
67 touch /var/lock/subsys/local
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将rclocal.txt文件的第2-5行保存为/tmp/out.txt文件：
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[root@svr5 ~]# sed -n '2,5w /tmp/out.txt' rclocal.txt
[root@svr5 ~]# cat /tmp/out.txt
2 #
3 # This script will be executed *after* all the other init scripts.
4 # You can put your own initialization stuff in here if you don't
5 # want to do the full Sys V style init stuff.
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上述操作与改用p重定向的效果相同：
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[root@svr5 ~]# sed -n '2,5p' rclocal.txt > /tmp/out.txt
[root@svr5 ~]# cat /tmp/out.txt
2 #
3 # This script will be executed *after* all the other init scripts.
4 # You can put your own initialization stuff in here if you don't
5 # want to do the full Sys V style init stuff.
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再比如：将rclocal.txt文件中包含“init”的行保存为/tmp/out.txt文件：
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[root@svr5 ~]# sed -n '/init/w /tmp/out.txt' rclocal.txt
[root@svr5 ~]# cat /tmp/out.txt
3 # This script will be executed *after* all the other init scripts.
4 # You can put your own initialization stuff in here if you don't
5 # want to do the full Sys V style init stuff.
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效果等同于：
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[root@svr5 ~]# sed -n '/init/p' rclocal.txt > /tmp/out.txt
[root@svr5 ~]# cat /tmp/out.txt
3 # This script will be executed *after* all the other init scripts.
4 # You can put your own initialization stuff in here if you don't
5 # want to do the full Sys V style init stuff.
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2．sed的复制粘贴操作
1）基本动作指令
复制到剪贴板：
H：模式空间 ---[追加]--->保持空间
h：模式空间 ---[覆盖]--->保持空间
读取剪贴板内容并粘贴：
G：保持空间 ---[追加]--->模式空间
g：模式空间 ---[覆盖]--->保持空间
若要实现“剪切”操作，实际上就是先“复制”再“删除”。
讲一下sed的2个空间：
模式空间：
--存放当前处理的行，将处理结果输出
--若当前行不符合处理条件，则原样输出
--处理完当前行再读入下一行来处理
保持空间：
--作用类似于”剪贴板“
--默认存放一个空行（换行符\n）
2）复制操作练习
还以rclocal.txt文件为例：
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[root@svr5 ~]# cat rclocal.txt
1 #!/bin/sh
2 #
3 # This script will be executed *after* all the other init scripts.
4 # You can put your own initialization stuff in here if you don't
5 # want to do the full Sys V style init stuff.
67 touch /var/lock/subsys/local
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将第rclocal.txt文件的第1-3行内容复制到文件末尾：
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[root@svr5 ~]# sed '1,3H;$G' rclocal.txt
1 #!/bin/sh
2 #
3 # This script will be executed *after* all the other init scripts.
4 # You can put your own initialization stuff in here if you don't
5 # want to do the full Sys V style init stuff.
67 touch /var/lock/subsys/local
1 #!/bin/sh
2 #
3 # This script will be executed *after* all the other init scripts.
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从上述结果可以发现，使用G粘贴操作的效果是追加。但是，文件原内容与新追加的文本之间还有一个空行，这是怎么来的呢？这是保持空间默认的内容“\n”，追加操作时就保留了。那么，如果将G追加改为g覆盖来粘贴，结果会怎么样呢？看看：
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[root@svr5 ~]# sed '1,3H;$g' rclocal.txt
1 #!/bin/sh
2 #
3 # This script will be executed *after* all the other init scripts.
4 # You can put your own initialization stuff in here if you don't
5 # want to do the full Sys V style init stuff.
61 #!/bin/sh
2 #
3 # This script will be executed *after* all the other init scripts.
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什么情况？把原文件的最后一行给覆盖了。如果既要保留原文件的所有内容，又想复制前3行到文件末尾，而且不希望有空行分开，怎么办呢？把复制操作H追加改成h覆盖试试看什么结果：
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[root@svr5 ~]# sed '1,3h;$G' rclocal.txt
1#!/bin/sh
2 #
3 # This script will be executed *after* all the other init scripts.
4 # You can put your own initialization stuff in here if you don't
5 # want to do the full Sys V style init stuff.
67 touch /var/lock/subsys/local
8 # This script will be executed *after* all the other init scripts.
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这下原文件内容是保留了，空行也没了，但是追加的内容却只有第3行，为什么？
因为sed是逐行处理的，所以每次h覆盖操作都会清空原来存放在保持空间的文本，也就是说用h复制第1行到保持空间后，默认的“\n”就没了；再用h复制第2行到保持空间后，前一次复制过去的第1行文本又没了；再用h复制第3行到保持空间后，前一次复制过去的第2行文本又没了，…… 于是，最终只有匹配的最后一行能够成功添加。
总和上述分析，我们可以在复制第一行的时候用h覆盖，而以后的每一行用H追加，这样就可以完美无空行的追加匹配行了：
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[root@svr5 ~]# sed '1h;2,3H;$G' rclocal.txt
1 #!/bin/sh
2 #
3 # This script will be executed *after* all the other init scripts.
4 # You can put your own initialization stuff in here if you don't
5 # want to do the full Sys V style init stuff.
67 touch /var/lock/subsys/local
1 #!/bin/sh
2 #
3 # This script will be executed *after* all the other init scripts.
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3）剪切操作练习
将rclocal.txt文件的第1-4行转移到文件末尾：
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[root@svr5 ~]# sed '1{h;d};2,4{H;d};$G' rclocal.txt
5 # want to do the full Sys V style init stuff.
67 touch /var/lock/subsys/local
1 #!/bin/sh
2 #
3 # This script will be executed *after* all the other init scripts.
4 # You can put your own initialization stuff in here if you don't
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将包含单词“init”的行剪切到文件末尾，保留默认的空行分隔：
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[root@svr5 ~]# sed '/\<init\>/{H;d};$G' rclocal.txt
1 #!/bin/sh
2 #
4 # You can put your own initialization stuff in here if you don't
67 touch /var/lock/subsys/local
3 # This script will be executed *after* all the other init scripts.
5 # want to do the full Sys V style init stuff.
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二、扩展
1．sed逐字符替换
sed的s操作可实现字符串替换，而另一个操作y操作可实现逐个字符替换。
什么意思呢？对比一下：
's/OLD/NEW/g' ，处理方式为整串匹配，只匹配完整的字符串“OLD”，对单个字符“O”、“L”或者“D”无效，而且替换前后的字符串长度可以不相同（比如，“OLD”可替换为“NEWNEW”）。实现的效果是——将文本中所有的字符串“OLD”替换为“NEW”。
'y/abcd/ABCD/'，处理的方式为逐个字符依次替换，替换前后的内容必须一一对应、数量一致。实现的效果是——将文件内所有的字符“a”替换为“A”、字符“b”替换为“B”、字符“c”替换为“C”、字符“d”替换为“D”。
下面仍以rclocal.txt文件为例，测试一下y操作的相关效果。
确认rclocal.txt文件内容：
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[root@svr5 ~]# cat rclocal.txt
1 #!/bin/sh
.2 #
3 # This script will be executed *after* all the other init scripts.
4 # You can put your own initialization stuff in here if you don't
5 # want to do the full Sys V style init stuff.
67 touch /var/lock/subsys/local
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1）将所有的小写字母i替换为大写的I：
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[root@svr5 ~]# sed 'y/i/I/' rclocal.txt
1 #!/bIn/sh
2 #
.3 # ThIs scrIpt wIll be executed *after* all the other InIt scrIpts.
4 # You can put your own InItIalIzatIon stuff In here If you don't
5 # want to do the full Sys V style InIt stuff.
.67 touch /var/lock/subsys/local
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等效于：
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[root@svr5 ~]# sed 's/i/I/g' rclocal.txt
1 #!/bIn/sh
2 #
3 # ThIs scrIpt wIll be executed *after* all the other InIt scrIpts.
4 # You can put your own InItIalIzatIon stuff In here If you don't
5 # want to do the full Sys V style InIt stuff.
67 touch /var/lock/subsys/local
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2）将所有的小写字母a、e、l替换为大写：
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[root@svr5 ~]# sed 'y/ael/AEL/' rclocal.txt
1 #!/bin/sh
2 #
3 # This script wiLL bE ExEcutEd *AftEr* ALL thE othEr init scripts.
4 # You cAn put your own initiALizAtion stuff in hErE if you don't
5 # wAnt to do thE fuLL Sys V styLE init stuff.
67 touch /vAr/Lock/subsys/LocAL
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等效于:
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[root@svr5 ~]# sed 's/a/A/g;s/e/E/g;s/l/L/g' rclocal.txt
1 #!/bin/sh
2 #
3 # This script wiLL bE ExEcutEd *AftEr* ALL thE othEr init scripts.
4 # You cAn put your own initiALizAtion stuff in hErE if you don't
5 # wAnt to do thE fuLL Sys V styLE init stuff.
67 touch /vAr/Lock/subsys/LocAL
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3）将所有的字符a变为数字1、字符e变为数字5、字符l变为变为字符X：
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[root@svr5 ~]# sed 'y/ael/159/' rclocal.txt
1 #!/bin/sh
2 #
3 # This script wi99 b5 5x5cut5d *1ft5r* 199 th5 oth5r init scripts.
4 # You c1n put your own initi19iz1tion stuff in h5r5 if you don't
5 # w1nt to do th5 fu99 Sys V sty95 init stuff.
67 touch /v1r/9ock/subsys/9oc19
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2．单词的大小写转换
将匹配结果转大写可用\U&、转小写可用\L&，这里的&为调用的匹配串。
还以前面的rclocal.txt文件为例，确认内容如下：
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[root@svr5 ~]# cat rclocal.txt
1 #!/bin/sh
2 #
3 # This script will be executed *after* all the other init scripts.
.4 # You can put your own initialization stuff in here if you don't
5 # want to do the full Sys V style init stuff.
67 touch /var/lock/subsys/local
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1）将所有的小写字母转为大写：
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[root@svr5 ~]# sed 's/[a-z]/\U&/g' rclocal.txt
1 #!/BIN/SH
2 #
3 # THIS SCRIPT WILL BE EXECUTED *AFTER* ALL THE OTHER INIT SCRIPTS.
4 # YOU CAN PUT YOUR OWN INITIALIZATION STUFF IN HERE IF YOU DON'T
5 # WANT TO DO THE FULL SYS V STYLE INIT STUFF.
67 TOUCH /VAR/LOCK/SUBSYS/LOCAL
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等效于：
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[root@svr5 ~]# cat rclocal.txt | tr [:lower:] [:upper:]
1 #!/BIN/SH
2 #
3 # THIS SCRIPT WILL BE EXECUTED *AFTER* ALL THE OTHER INIT SCRIPTS.
4 # YOU CAN PUT YOUR OWN INITIALIZATION STUFF IN HERE IF YOU DON'T
5 # WANT TO DO THE FULL SYS V STYLE INIT STUFF.
67 TOUCH /VAR/LOCK/SUBSYS/LOCAL
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2）将所有的大写字母转为小写：
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[root@svr5 ~]# sed 's/[A-Z]/\L&/g' rclocal.txt
1 #!/bin/sh
2 #
3 # this script will be executed *after* all the other init scripts.
4 # you can put your own initialization stuff in here if you don't
5 # want to do the full sys v style init stuff.
67 touch /var/lock/subsys/local
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等效于：
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[root@svr5 ~]# cat rclocal.txt | tr [:upper:] [:lower:]
1 #!/bin/sh
2 #
3 # this script will be executed *after* all the other init scripts.
4 # you can put your own initialization stuff in here if you don't
5 # want to do the full sys v style init stuff.
67 touch /var/lock/subsys/local
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3）将每个单词的首字母大写：
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[root@svr5 ~]# sed -r 's/\b[a-Z]/\U&/g' rclocal.txt
1 #!/Bin/Sh
2 #
3 # This Script Will Be Executed *After* All The Other Init Scripts.
4 # You Can Put Your Own Initialization Stuff In Here If You Don'T
5 # Want To Do The Full Sys V Style Init Stuff.
67 Touch /Var/Lock/Subsys/Local
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4）将每个单词的首字母大写，其余字母小写：
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[root@svr5 ~]# sed -r 's/([a-Z])([a-Z]+)/\U\1\L\2/g' rclocal.txt
1 #!/Bin/Sh
2 #
3 # This Script Will Be Executed *After* All The Other Init Scripts.
4 # You Can Put Your Own Initialization Stuff In Here If You Don't
5 # Want To Do The Full Sys V Style Init Stuff.
67 Touch /Var/Lock/Subsys/Local
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总结：
1、若要实现“剪切”操作，实际上就是先“复制”再“删除”。
2、因为保持空间默认会有一个换行符号，所以把模式空间的内容放到保持空间的时候，第一行用h覆盖来把换行符给覆盖掉，这样就不会出现一行空格
本文转自Jx战壕 51CTO博客，原文链接：http://blog.51cto.com/xujpxm/1391849，如需转载请自行联系原作者