shell 中 grep、sed、awk 命令

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原文:http://blog.csdn.net/chenhanzhun/article/details/44133789

grep 命令

grep命令基本语法

grep命令是打印匹配文本行,其全称为 Global Search Regular Expression and Print out the line;基本语法如下:

<code class="hljs css has-numbering" style="display: block; padding: 0px; color: inherit; box-sizing: border-box; font-family: 'Source Code Pro', monospace;font-size:undefined; white-space: pre; border-radius: 0px; word-wrap: normal; background: transparent;"><span class="hljs-tag" style="color: rgb(0, 0, 0); box-sizing: border-box;">grep</span> <span class="hljs-attr_selector" style="color: rgb(0, 136, 0); box-sizing: border-box;">[OPTIONS]</span> <span class="hljs-tag" style="color: rgb(0, 0, 0); box-sizing: border-box;">PATTERN</span> <span class="hljs-attr_selector" style="color: rgb(0, 136, 0); box-sizing: border-box;">[FILE...]</span><span class="hljs-tag" style="color: rgb(0, 0, 0); box-sizing: border-box;">grep</span> <span class="hljs-attr_selector" style="color: rgb(0, 136, 0); box-sizing: border-box;">[OPTIONS]</span> <span class="hljs-attr_selector" style="color: rgb(0, 136, 0); box-sizing: border-box;">[-e PATTERN | -f FILE]</span> <span class="hljs-attr_selector" style="color: rgb(0, 136, 0); box-sizing: border-box;">[FILE...]</span></code><ul class="pre-numbering" style="box-sizing: border-box; position: absolute; width: 50px; top: 0px; left: 0px; margin: 0px; padding: 6px 0px 40px; border-right-width: 1px; border-right-style: solid; border-right-color: rgb(221, 221, 221); list-style: none; text-align: right; background-color: rgb(238, 238, 238);"><li style="box-sizing: border-box; padding: 0px 5px;">1</li><li style="box-sizing: border-box; padding: 0px 5px;">2</li><li style="box-sizing: border-box; padding: 0px 5px;">3</li></ul>

其中,OPTIONS表示选项;PATTERN表示匹配模式,匹配模式可以是字符串、变量、正则表达式,若匹配模式中含义空格,则需要使用双引号将匹配模式引起来;FILE表示一系列文件;grep命令从文件中搜索满足指定匹配模式的文本行,并打印出来。

在前面文章《正则表达式》可知,正则表达式的分类为:

  • 基本正则表达式(Basic Regular Expression):Basic RegEx,简称 BRE
  • 扩展正则表达式(Extended Regular Expression):Extended RegEx,简称 ERE
  • Perl 正则表达式(Perl Regular Expression):Perl RegEx,简称 PCRE

grep命令根据不同的参数支持不同的正则表达式:

  • grep命令后不跟任何参数(默认),则表示要使用“BRE”;
  • grep命令后跟-E参数,则表示要使用“ERE”;
  • grep命令后跟-P参数,则表示要使用“PCRE”;

常用OPTIONS选项如下表所示:

选项说明-E指定 PATTERN 匹配模式为扩展正则表达式-F指定 PATTERN 匹配模式为固定的字符串-G指定 PATTERN 匹配模式为基本正则表达式-P指定 PATTERN 匹配模式为 Perl 正则表达式  -e PATTERN指定 PATTERN 为一个或多个搜索模式-f FILE指定包含搜索模式的 FILE-i匹配是忽略字母大小写-v显示所有与匹配模式不匹配的文本行-w执行单词搜索-x显示与指定模式精确匹配而不含其他字符的文本行-y与选项 -i 相同功能  -c只打印匹配的文本行的行数,不显示匹配内容-l只显示匹配文本行的文件名,不显示匹配内容-n列出所有匹配的文本行,并显示行号-r递归搜索目录(当前目录及其各级子目录)-s不显示错误信息

流编辑器 sed

sed命令

sed命令从文件或者标准输入中一次读取一行数据,将该行数据复制到缓冲区,然后读取命令行或脚本的编辑子命令,对缓冲区中的文本行进行编辑。重复此工作,直到所有文本行都处理完毕。

sed命令编辑的是文件是原始文件在缓冲区中的副本,并不影响原始文件,但是可以把编辑结果通过输出重定向保存起来。

sed命令的基本语法如下所示:

<code class="hljs r has-numbering" style="display: block; padding: 0px; color: inherit; box-sizing: border-box; font-family: 'Source Code Pro', monospace;font-size:undefined; white-space: pre; border-radius: 0px; word-wrap: normal; background: transparent;">sed [OPTION]<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">...</span> {script} [input-file]<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">...</span></code><ul class="pre-numbering" style="box-sizing: border-box; position: absolute; width: 50px; top: 0px; left: 0px; margin: 0px; padding: 6px 0px 40px; border-right-width: 1px; border-right-style: solid; border-right-color: rgb(221, 221, 221); list-style: none; text-align: right; background-color: rgb(238, 238, 238);"><li style="box-sizing: border-box; padding: 0px 5px;">1</li></ul>

常用选项OPTION如下表所示:

选项说明-n取消默认输出-e script允许执行多个脚本-f script-file从脚本文件中读取命令-i直接修改原始文件-l N指定行长度为 N-r在脚本中使用扩展正则表达式-s把文件作为单独文件-u最低限度的缓存输入与输出

文本行定位

sed命令提供了两种方式来实现文本行的定位:行号定位正则表达式定位

行号定位

  • 定位某个特定的行nn是一个整数,表示定位到文本的第n行;
  • 定位某段连续的行n,mnm都是整数,表示定位到起始行为n,终止行为m的文本行;
  • 指定起始行和步长start~step:起始行为start,步长为step
  • 第一行1和最后一行$1表示第一行,$表示最后一行;
  • 指定某行后面的几行n,+x:表示从第n行开始到后面的x行;

正则表达式定位

sed命令使用正则表达式定位文本行的语法如下所示:

<code class="hljs vala has-numbering" style="display: block; padding: 0px; color: inherit; box-sizing: border-box; font-family: 'Source Code Pro', monospace;font-size:undefined; white-space: pre; border-radius: 0px; word-wrap: normal; background: transparent;"><span class="hljs-preprocessor" style="color: rgb(68, 68, 68); box-sizing: border-box;">#regexp 表示正则表达式</span>/regexp/</code><ul class="pre-numbering" style="box-sizing: border-box; position: absolute; width: 50px; top: 0px; left: 0px; margin: 0px; padding: 6px 0px 40px; border-right-width: 1px; border-right-style: solid; border-right-color: rgb(221, 221, 221); list-style: none; text-align: right; background-color: rgb(238, 238, 238);"><li style="box-sizing: border-box; padding: 0px 5px;">1</li><li style="box-sizing: border-box; padding: 0px 5px;">2</li></ul>

sed命令的常用操作

sed命令的常用编辑命令有:打印、删除、增加、替换;其基本语法如下所示:

<code class="hljs css has-numbering" style="display: block; padding: 0px; color: inherit; box-sizing: border-box; font-family: 'Source Code Pro', monospace;font-size:undefined; white-space: pre; border-radius: 0px; word-wrap: normal; background: transparent;"><span class="hljs-attr_selector" style="color: rgb(0, 136, 0); box-sizing: border-box;">[address1[,address2]</span>] <span class="hljs-tag" style="color: rgb(0, 0, 0); box-sizing: border-box;">command</span> <span class="hljs-attr_selector" style="color: rgb(0, 136, 0); box-sizing: border-box;">[argument]</span></code><ul class="pre-numbering" style="box-sizing: border-box; position: absolute; width: 50px; top: 0px; left: 0px; margin: 0px; padding: 6px 0px 40px; border-right-width: 1px; border-right-style: solid; border-right-color: rgb(221, 221, 221); list-style: none; text-align: right; background-color: rgb(238, 238, 238);"><li style="box-sizing: border-box; padding: 0px 5px;">1</li></ul>

其中address称为位置参数,即上面的行定位;commandsed所提供的子命令,用来实现编辑操作;argument表示子命令的选项参数;

打印文本

sed命令中可通过位置参数和p命令打印所需要的文本行,其语法如下所示:

<code class="hljs css has-numbering" style="display: block; padding: 0px; color: inherit; box-sizing: border-box; font-family: 'Source Code Pro', monospace;font-size:undefined; white-space: pre; border-radius: 0px; word-wrap: normal; background: transparent;"><span class="hljs-attr_selector" style="color: rgb(0, 136, 0); box-sizing: border-box;">[address1[,address2]</span>] <span class="hljs-tag" style="color: rgb(0, 0, 0); box-sizing: border-box;">p</span></code><ul class="pre-numbering" style="box-sizing: border-box; position: absolute; width: 50px; top: 0px; left: 0px; margin: 0px; padding: 6px 0px 40px; border-right-width: 1px; border-right-style: solid; border-right-color: rgb(221, 221, 221); list-style: none; text-align: right; background-color: rgb(238, 238, 238);"><li style="box-sizing: border-box; padding: 0px 5px;">1</li></ul>

例如:

<code class="hljs bash has-numbering" style="display: block; padding: 0px; color: inherit; box-sizing: border-box; font-family: 'Source Code Pro', monospace;font-size:undefined; white-space: pre; border-radius: 0px; word-wrap: normal; background: transparent;"><span class="hljs-shebang" style="color: rgb(0, 102, 102); box-sizing: border-box;">#! /bin/bash</span><span class="hljs-comment" style="color: rgb(136, 0, 0); box-sizing: border-box;">#输出第1~4行文本,注意1,3p之间是单引号</span>sed -n <span class="hljs-string" style="color: rgb(0, 136, 0); box-sizing: border-box;">'1,3p'</span> test.txt<span class="hljs-comment" style="color: rgb(136, 0, 0); box-sizing: border-box;">#输出以Lin开头的文本行</span>result=`sed -n <span class="hljs-string" style="color: rgb(0, 136, 0); box-sizing: border-box;">'/^Lin/ p'</span> test.txt`<span class="hljs-built_in" style="color: rgb(102, 0, 102); box-sizing: border-box;">echo</span> <span class="hljs-string" style="color: rgb(0, 136, 0); box-sizing: border-box;">"<span class="hljs-variable" style="color: rgb(102, 0, 102); box-sizing: border-box;">$result</span>"</span></code><ul class="pre-numbering" style="box-sizing: border-box; position: absolute; width: 50px; top: 0px; left: 0px; margin: 0px; padding: 6px 0px 40px; border-right-width: 1px; border-right-style: solid; border-right-color: rgb(221, 221, 221); list-style: none; text-align: right; background-color: rgb(238, 238, 238);"><li style="box-sizing: border-box; padding: 0px 5px;">1</li><li style="box-sizing: border-box; padding: 0px 5px;">2</li><li style="box-sizing: border-box; padding: 0px 5px;">3</li><li style="box-sizing: border-box; padding: 0px 5px;">4</li><li style="box-sizing: border-box; padding: 0px 5px;">5</li><li style="box-sizing: border-box; padding: 0px 5px;">6</li><li style="box-sizing: border-box; padding: 0px 5px;">7</li><li style="box-sizing: border-box; padding: 0px 5px;">8</li></ul>

替换文本

sed命令中可通过位置参数和s子命令替换文本行,其语法如下所示:

<code class="hljs coffeescript has-numbering" style="display: block; padding: 0px; color: inherit; box-sizing: border-box; font-family: 'Source Code Pro', monospace;font-size:undefined; white-space: pre; border-radius: 0px; word-wrap: normal; background: transparent;">[address1[,address2]] s<span class="hljs-regexp" style="color: rgb(0, 136, 0); box-sizing: border-box;">/pattern/replacemen/</span>[flag]</code><ul class="pre-numbering" style="box-sizing: border-box; position: absolute; width: 50px; top: 0px; left: 0px; margin: 0px; padding: 6px 0px 40px; border-right-width: 1px; border-right-style: solid; border-right-color: rgb(221, 221, 221); list-style: none; text-align: right; background-color: rgb(238, 238, 238);"><li style="box-sizing: border-box; padding: 0px 5px;">1</li></ul>

flag为替换标志,不同值会影响s子命令的行为;flag常用取值如下表所示:

取值说明g全局匹配,会替换文本行所有符合规则的字符串p替换第一个符合规则的字符串,并将缓冲区输出到标准输出w替换第一个符合规则的字符串,并将受影响的行输出到磁盘文件中十进制数n替换文本行中第n个符合规则的字符串空若不指定flag值,替换文本行中第一个符合规则的字符串

删除文本

sed命令中可通过位置参数和d子命令删除文本行,其语法如下所示:

<code class="hljs css has-numbering" style="display: block; padding: 0px; color: inherit; box-sizing: border-box; font-family: 'Source Code Pro', monospace;font-size:undefined; white-space: pre; border-radius: 0px; word-wrap: normal; background: transparent;"><span class="hljs-attr_selector" style="color: rgb(0, 136, 0); box-sizing: border-box;">[address1[,address2]</span>] <span class="hljs-tag" style="color: rgb(0, 0, 0); box-sizing: border-box;">d</span></code><ul class="pre-numbering" style="box-sizing: border-box; position: absolute; width: 50px; top: 0px; left: 0px; margin: 0px; padding: 6px 0px 40px; border-right-width: 1px; border-right-style: solid; border-right-color: rgb(221, 221, 221); list-style: none; text-align: right; background-color: rgb(238, 238, 238);"><li style="box-sizing: border-box; padding: 0px 5px;">1</li></ul>

增加文本

追加文本 
sed命令中可通过位置参数和a子命令追加文本行,其语法如下所示:

<code class="hljs vala has-numbering" style="display: block; padding: 0px; color: inherit; box-sizing: border-box; font-family: 'Source Code Pro', monospace;font-size:undefined; white-space: pre; border-radius: 0px; word-wrap: normal; background: transparent;"><span class="hljs-preprocessor" style="color: rgb(68, 68, 68); box-sizing: border-box;">#将string插入到address1位置后面</span>[address1] a <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">string</span> </code><ul class="pre-numbering" style="box-sizing: border-box; position: absolute; width: 50px; top: 0px; left: 0px; margin: 0px; padding: 6px 0px 40px; border-right-width: 1px; border-right-style: solid; border-right-color: rgb(221, 221, 221); list-style: none; text-align: right; background-color: rgb(238, 238, 238);"><li style="box-sizing: border-box; padding: 0px 5px;">1</li><li style="box-sizing: border-box; padding: 0px 5px;">2</li></ul>

插入文本 
sed命令中可通过位置参数和i子命令插入文本行,其语法如下所示:

<code class="hljs vala has-numbering" style="display: block; padding: 0px; color: inherit; box-sizing: border-box; font-family: 'Source Code Pro', monospace;font-size:undefined; white-space: pre; border-radius: 0px; word-wrap: normal; background: transparent;"><span class="hljs-preprocessor" style="color: rgb(68, 68, 68); box-sizing: border-box;">#将string插入到address1位置前面</span>[address1] i <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">string</span> </code><ul class="pre-numbering" style="box-sizing: border-box; position: absolute; width: 50px; top: 0px; left: 0px; margin: 0px; padding: 6px 0px 40px; border-right-width: 1px; border-right-style: solid; border-right-color: rgb(221, 221, 221); list-style: none; text-align: right; background-color: rgb(238, 238, 238);"><li style="box-sizing: border-box; padding: 0px 5px;">1</li><li style="box-sizing: border-box; padding: 0px 5px;">2</li></ul>

组合命令

sed命令支持将多个子命令组合在一起使用;具体方式如下所示:

  • 使用-e选项:-e选项可以将多个子命令组合在一起使用;例如:
<code class="hljs bash has-numbering" style="display: block; padding: 0px; color: inherit; box-sizing: border-box; font-family: 'Source Code Pro', monospace;font-size:undefined; white-space: pre; border-radius: 0px; word-wrap: normal; background: transparent;"><span class="hljs-shebang" style="color: rgb(0, 102, 102); box-sizing: border-box;">#! /bin/bash</span><span class="hljs-comment" style="color: rgb(136, 0, 0); box-sizing: border-box;">#将全部小写字母 e 替换成大写字母 E,并打印第 1 行到第 3 行文本行</span>result=`sed -n <span class="hljs-operator" style="box-sizing: border-box;">-e</span> <span class="hljs-string" style="color: rgb(0, 136, 0); box-sizing: border-box;">'s/e/E/g'</span> <span class="hljs-operator" style="box-sizing: border-box;">-e</span> <span class="hljs-string" style="color: rgb(0, 136, 0); box-sizing: border-box;">'1,3 p'</span> test.txt`<span class="hljs-built_in" style="color: rgb(102, 0, 102); box-sizing: border-box;">echo</span> <span class="hljs-string" style="color: rgb(0, 136, 0); box-sizing: border-box;">"<span class="hljs-variable" style="color: rgb(102, 0, 102); box-sizing: border-box;">$result</span>"</span></code><ul class="pre-numbering" style="box-sizing: border-box; position: absolute; width: 50px; top: 0px; left: 0px; margin: 0px; padding: 6px 0px 40px; border-right-width: 1px; border-right-style: solid; border-right-color: rgb(221, 221, 221); list-style: none; text-align: right; background-color: rgb(238, 238, 238);"><li style="box-sizing: border-box; padding: 0px 5px;">1</li><li style="box-sizing: border-box; padding: 0px 5px;">2</li><li style="box-sizing: border-box; padding: 0px 5px;">3</li><li style="box-sizing: border-box; padding: 0px 5px;">4</li><li style="box-sizing: border-box; padding: 0px 5px;">5</li></ul>
  • 使用分号;执行多个子命令: 
    其语法格式:
<code class="hljs bash has-numbering" style="display: block; padding: 0px; color: inherit; box-sizing: border-box; font-family: 'Source Code Pro', monospace;font-size:undefined; white-space: pre; border-radius: 0px; word-wrap: normal; background: transparent;">sed <span class="hljs-operator" style="box-sizing: border-box;">-e</span> <span class="hljs-string" style="color: rgb(0, 136, 0); box-sizing: border-box;">'command1; command2...'</span> filename</code><ul class="pre-numbering" style="box-sizing: border-box; position: absolute; width: 50px; top: 0px; left: 0px; margin: 0px; padding: 6px 0px 40px; border-right-width: 1px; border-right-style: solid; border-right-color: rgb(221, 221, 221); list-style: none; text-align: right; background-color: rgb(238, 238, 238);"><li style="box-sizing: border-box; padding: 0px 5px;">1</li></ul>

例如:

<code class="hljs bash has-numbering" style="display: block; padding: 0px; color: inherit; box-sizing: border-box; font-family: 'Source Code Pro', monospace;font-size:undefined; white-space: pre; border-radius: 0px; word-wrap: normal; background: transparent;"><span class="hljs-shebang" style="color: rgb(0, 102, 102); box-sizing: border-box;">#! /bin/bash</span><span class="hljs-comment" style="color: rgb(136, 0, 0); box-sizing: border-box;">#将全部小写字母 e 替换成大写字母 E,并打印第 1 行到第 3 行文本行</span>result=`sed -n <span class="hljs-operator" style="box-sizing: border-box;">-e</span> <span class="hljs-string" style="color: rgb(0, 136, 0); box-sizing: border-box;">'s/e/E/g; 1,3 p'</span> test.txt`<span class="hljs-built_in" style="color: rgb(102, 0, 102); box-sizing: border-box;">echo</span> <span class="hljs-string" style="color: rgb(0, 136, 0); box-sizing: border-box;">"<span class="hljs-variable" style="color: rgb(102, 0, 102); box-sizing: border-box;">$result</span>"</span></code><ul class="pre-numbering" style="box-sizing: border-box; position: absolute; width: 50px; top: 0px; left: 0px; margin: 0px; padding: 6px 0px 40px; border-right-width: 1px; border-right-style: solid; border-right-color: rgb(221, 221, 221); list-style: none; text-align: right; background-color: rgb(238, 238, 238);"><li style="box-sizing: border-box; padding: 0px 5px;">1</li><li style="box-sizing: border-box; padding: 0px 5px;">2</li><li style="box-sizing: border-box; padding: 0px 5px;">3</li><li style="box-sizing: border-box; padding: 0px 5px;">4</li><li style="box-sizing: border-box; padding: 0px 5px;">5</li></ul>
  • 对同一个地址使用多个子命令: 
    其语法格式:
<code class="hljs r has-numbering" style="display: block; padding: 0px; color: inherit; box-sizing: border-box; font-family: 'Source Code Pro', monospace;font-size:undefined; white-space: pre; border-radius: 0px; word-wrap: normal; background: transparent;">address{    command1    command2    command3    <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">...</span>}<span class="hljs-comment" style="color: rgb(136, 0, 0); box-sizing: border-box;">#或</span>[address] { command1;command2;command3;<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">...</span>}</code><ul class="pre-numbering" style="box-sizing: border-box; position: absolute; width: 50px; top: 0px; left: 0px; margin: 0px; padding: 6px 0px 40px; border-right-width: 1px; border-right-style: solid; border-right-color: rgb(221, 221, 221); list-style: none; text-align: right; background-color: rgb(238, 238, 238);"><li style="box-sizing: border-box; padding: 0px 5px;">1</li><li style="box-sizing: border-box; padding: 0px 5px;">2</li><li style="box-sizing: border-box; padding: 0px 5px;">3</li><li style="box-sizing: border-box; padding: 0px 5px;">4</li><li style="box-sizing: border-box; padding: 0px 5px;">5</li><li style="box-sizing: border-box; padding: 0px 5px;">6</li><li style="box-sizing: border-box; padding: 0px 5px;">7</li><li style="box-sizing: border-box; padding: 0px 5px;">8</li></ul>

sed脚本文件

可以将多个子命令写成后缀名为.sedsed脚本文件,sed脚本文件内容只需将各个子命令依次列出来,不必使用引号,若将多个子命令写在同一行,则不同子命令之间需使用分号隔开。调用sed脚本文件的格式如下:

<code class="hljs bash has-numbering" style="display: block; padding: 0px; color: inherit; box-sizing: border-box; font-family: 'Source Code Pro', monospace;font-size:undefined; white-space: pre; border-radius: 0px; word-wrap: normal; background: transparent;">sed <span class="hljs-operator" style="box-sizing: border-box;">-f</span> script</code><ul class="pre-numbering" style="box-sizing: border-box; position: absolute; width: 50px; top: 0px; left: 0px; margin: 0px; padding: 6px 0px 40px; border-right-width: 1px; border-right-style: solid; border-right-color: rgb(221, 221, 221); list-style: none; text-align: right; background-color: rgb(238, 238, 238);"><li style="box-sizing: border-box; padding: 0px 5px;">1</li></ul>

awk命令

awk命令的基本语法

awk命令是一个文本处理工具,其基本语法如下所示:

<code class="hljs mathematica has-numbering" style="display: block; padding: 0px; color: inherit; box-sizing: border-box; font-family: 'Source Code Pro', monospace;font-size:undefined; white-space: pre; border-radius: 0px; word-wrap: normal; background: transparent;">awk pattern <span class="hljs-list" style="box-sizing: border-box;">{ actions }</span></code><ul class="pre-numbering" style="box-sizing: border-box; position: absolute; width: 50px; top: 0px; left: 0px; margin: 0px; padding: 6px 0px 40px; border-right-width: 1px; border-right-style: solid; border-right-color: rgb(221, 221, 221); list-style: none; text-align: right; background-color: rgb(238, 238, 238);"><li style="box-sizing: border-box; padding: 0px 5px;">1</li></ul>

其中,pattern表示匹配模式,actions表示要执行的操作;即对符合pattern匹配模式的文本行执行actions操作;若省略pattern匹配模式,则表示对所有文本行执行actions操作;若省略pattern 
匹配模式,则把匹配成功的文本行打印输出;但是不能同时省略patternactions

pattern匹配模式可以是以下其中一种:

  • 正则表达式;
  • 关系表达式;
  • 模式1,模式2:指定一行的范围;
  • BEGIN:指定在第一行文本被处理之前所发生的操作;
  • END:指定在最后一行文本被读取之后发送的操作;

actions命令由一个或多个命令、函数或者表达式组成,他们之间由换行符或分号隔开,并位于大括号内,一般有以下四种情况:

  • 变量或数组赋值;
  • 输出命令,例如printfprint
  • 内置函数;
  • 流控制语句,例如ifwhilefor语句;

awk命令的执行方式:

  • 通过命令行执行:其语法:
<code class="hljs bash has-numbering" style="display: block; padding: 0px; color: inherit; box-sizing: border-box; font-family: 'Source Code Pro', monospace;font-size:undefined; white-space: pre; border-radius: 0px; word-wrap: normal; background: transparent;">awk <span class="hljs-string" style="color: rgb(0, 136, 0); box-sizing: border-box;">'awk程序语句'</span> 数据文件</code><ul class="pre-numbering" style="box-sizing: border-box; position: absolute; width: 50px; top: 0px; left: 0px; margin: 0px; padding: 6px 0px 40px; border-right-width: 1px; border-right-style: solid; border-right-color: rgb(221, 221, 221); list-style: none; text-align: right; background-color: rgb(238, 238, 238);"><li style="box-sizing: border-box; padding: 0px 5px;">1</li></ul>
  • 执行 awk脚本:其语法:
<code class="hljs bash has-numbering" style="display: block; padding: 0px; color: inherit; box-sizing: border-box; font-family: 'Source Code Pro', monospace;font-size:undefined; white-space: pre; border-radius: 0px; word-wrap: normal; background: transparent;"><span class="hljs-comment" style="color: rgb(136, 0, 0); box-sizing: border-box;">#注意:awk脚本文件是后缀名为.awk的文件</span>awk <span class="hljs-operator" style="box-sizing: border-box;">-f</span> awk脚本文件 数据文件</code><ul class="pre-numbering" style="box-sizing: border-box; position: absolute; width: 50px; top: 0px; left: 0px; margin: 0px; padding: 6px 0px 40px; border-right-width: 1px; border-right-style: solid; border-right-color: rgb(221, 221, 221); list-style: none; text-align: right; background-color: rgb(238, 238, 238);"><li style="box-sizing: border-box; padding: 0px 5px;">1</li><li style="box-sizing: border-box; padding: 0px 5px;">2</li></ul>
  • 可执行脚本文件:即在 shell文件中指定解析器为#! /bin/awk -f

awk命令的匹配模式

awk命令的匹配模式主要包括:关系表达式、正则表达式、混合模式、区间模式、BEGIN模式、END模式等。

关系表达式

awk命令中的关系运算符如下表所示:

运算符说明>大于>=大于等于<小于<=小于等于==等于!=不等于~匹配运算:例如$1~/^A表示匹配第一个字段以字符A开头的记录!~不匹配运算

正则表达式

awk支持以正则表达式为匹配模式,其基本语法如下所示:

<code class="hljs vala has-numbering" style="display: block; padding: 0px; color: inherit; box-sizing: border-box; font-family: 'Source Code Pro', monospace;font-size:undefined; white-space: pre; border-radius: 0px; word-wrap: normal; background: transparent;"><span class="hljs-preprocessor" style="color: rgb(68, 68, 68); box-sizing: border-box;">#regexp 表示正则表达式</span>/regexp/</code><ul class="pre-numbering" style="box-sizing: border-box; position: absolute; width: 50px; top: 0px; left: 0px; margin: 0px; padding: 6px 0px 40px; border-right-width: 1px; border-right-style: solid; border-right-color: rgb(221, 221, 221); list-style: none; text-align: right; background-color: rgb(238, 238, 238);"><li style="box-sizing: border-box; padding: 0px 5px;">1</li><li style="box-sizing: border-box; padding: 0px 5px;">2</li></ul>

例如:输出以字符u开头的文本行

<code class="hljs bash has-numbering" style="display: block; padding: 0px; color: inherit; box-sizing: border-box; font-family: 'Source Code Pro', monospace;font-size:undefined; white-space: pre; border-radius: 0px; word-wrap: normal; background: transparent;"><span class="hljs-shebang" style="color: rgb(0, 102, 102); box-sizing: border-box;">#! /bin/bash</span><span class="hljs-comment" style="color: rgb(136, 0, 0); box-sizing: border-box;">#filename:test.sh</span>result=`awk <span class="hljs-string" style="color: rgb(0, 136, 0); box-sizing: border-box;">'/^u/ {print}'</span> shell.md`<span class="hljs-built_in" style="color: rgb(102, 0, 102); box-sizing: border-box;">echo</span> <span class="hljs-string" style="color: rgb(0, 136, 0); box-sizing: border-box;">"<span class="hljs-variable" style="color: rgb(102, 0, 102); box-sizing: border-box;">$result</span>"</span><span class="hljs-comment" style="color: rgb(136, 0, 0); box-sizing: border-box;">#输出结果:</span>$ sh test.sh <span class="hljs-built_in" style="color: rgb(102, 0, 102); box-sizing: border-box;">unset</span> variable_name<span class="hljs-built_in" style="color: rgb(102, 0, 102); box-sizing: border-box;">unset</span> varuntiluntil<span class="hljs-built_in" style="color: rgb(102, 0, 102); box-sizing: border-box;">unset</span> <span class="hljs-operator" style="box-sizing: border-box;">-f</span> 函数名</code><ul class="pre-numbering" style="box-sizing: border-box; position: absolute; width: 50px; top: 0px; left: 0px; margin: 0px; padding: 6px 0px 40px; border-right-width: 1px; border-right-style: solid; border-right-color: rgb(221, 221, 221); list-style: none; text-align: right; background-color: rgb(238, 238, 238);"><li style="box-sizing: border-box; padding: 0px 5px;">1</li><li style="box-sizing: border-box; padding: 0px 5px;">2</li><li style="box-sizing: border-box; padding: 0px 5px;">3</li><li style="box-sizing: border-box; padding: 0px 5px;">4</li><li style="box-sizing: border-box; padding: 0px 5px;">5</li><li style="box-sizing: border-box; padding: 0px 5px;">6</li><li style="box-sizing: border-box; padding: 0px 5px;">7</li><li style="box-sizing: border-box; padding: 0px 5px;">8</li><li style="box-sizing: border-box; padding: 0px 5px;">9</li><li style="box-sizing: border-box; padding: 0px 5px;">10</li><li style="box-sizing: border-box; padding: 0px 5px;">11</li><li style="box-sizing: border-box; padding: 0px 5px;">12</li><li style="box-sizing: border-box; padding: 0px 5px;">13</li><li style="box-sizing: border-box; padding: 0px 5px;">14</li></ul>

混合模式

awk命令的匹配模式中,可以通过逻辑运算符使用多个表达式组成命令;基本逻辑运算符如下表所示:

运算符说明&&逻辑与||逻辑或!逻辑非

区间模式

awk命令支持区间模式,其语法如下:

<code class="hljs  has-numbering" style="display: block; padding: 0px; color: inherit; box-sizing: border-box; font-family: 'Source Code Pro', monospace;font-size:undefined; white-space: pre; border-radius: 0px; word-wrap: normal; background: transparent;">pattern1, pattern2</code><ul class="pre-numbering" style="box-sizing: border-box; position: absolute; width: 50px; top: 0px; left: 0px; margin: 0px; padding: 6px 0px 40px; border-right-width: 1px; border-right-style: solid; border-right-color: rgb(221, 221, 221); list-style: none; text-align: right; background-color: rgb(238, 238, 238);"><li style="box-sizing: border-box; padding: 0px 5px;">1</li></ul>

例如:第一个匹配模式是:以字符串one开头的文本行;第二个匹配模式是:第3字段等于14的文本行;所有符合这两个匹配模式之间的文本行都会被输出;

<code class="hljs bash has-numbering" style="display: block; padding: 0px; color: inherit; box-sizing: border-box; font-family: 'Source Code Pro', monospace;font-size:undefined; white-space: pre; border-radius: 0px; word-wrap: normal; background: transparent;"><span class="hljs-shebang" style="color: rgb(0, 102, 102); box-sizing: border-box;">#!/bin/bash</span><span class="hljs-comment" style="color: rgb(136, 0, 0); box-sizing: border-box;">#filename:test.sh</span>result=`awk <span class="hljs-string" style="color: rgb(0, 136, 0); box-sizing: border-box;">'/^one/ , $3==14 {print}'</span> test.txt`<span class="hljs-built_in" style="color: rgb(102, 0, 102); box-sizing: border-box;">echo</span> <span class="hljs-string" style="color: rgb(0, 136, 0); box-sizing: border-box;">"<span class="hljs-variable" style="color: rgb(102, 0, 102); box-sizing: border-box;">$result</span>"</span><span class="hljs-comment" style="color: rgb(136, 0, 0); box-sizing: border-box;">#执行结果:</span>$ sh test.sh one     <span class="hljs-number" style="color: rgb(0, 102, 102); box-sizing: border-box;">10</span>  <span class="hljs-number" style="color: rgb(0, 102, 102); box-sizing: border-box;">20</span>  <span class="hljs-number" style="color: rgb(0, 102, 102); box-sizing: border-box;">30</span>two     <span class="hljs-number" style="color: rgb(0, 102, 102); box-sizing: border-box;">15</span>  <span class="hljs-number" style="color: rgb(0, 102, 102); box-sizing: border-box;">25</span>  <span class="hljs-number" style="color: rgb(0, 102, 102); box-sizing: border-box;">20</span>three   <span class="hljs-number" style="color: rgb(0, 102, 102); box-sizing: border-box;">20</span>  <span class="hljs-number" style="color: rgb(0, 102, 102); box-sizing: border-box;">15</span>  <span class="hljs-number" style="color: rgb(0, 102, 102); box-sizing: border-box;">31</span>four    <span class="hljs-number" style="color: rgb(0, 102, 102); box-sizing: border-box;">16</span>  <span class="hljs-number" style="color: rgb(0, 102, 102); box-sizing: border-box;">26</span>  <span class="hljs-number" style="color: rgb(0, 102, 102); box-sizing: border-box;">35</span>five    <span class="hljs-number" style="color: rgb(0, 102, 102); box-sizing: border-box;">11</span>  <span class="hljs-number" style="color: rgb(0, 102, 102); box-sizing: border-box;">14</span>  <span class="hljs-number" style="color: rgb(0, 102, 102); box-sizing: border-box;">40</span></code><ul class="pre-numbering" style="box-sizing: border-box; position: absolute; width: 50px; top: 0px; left: 0px; margin: 0px; padding: 6px 0px 40px; border-right-width: 1px; border-right-style: solid; border-right-color: rgb(221, 221, 221); list-style: none; text-align: right; background-color: rgb(238, 238, 238);"><li style="box-sizing: border-box; padding: 0px 5px;">1</li><li style="box-sizing: border-box; padding: 0px 5px;">2</li><li style="box-sizing: border-box; padding: 0px 5px;">3</li><li style="box-sizing: border-box; padding: 0px 5px;">4</li><li style="box-sizing: border-box; padding: 0px 5px;">5</li><li style="box-sizing: border-box; padding: 0px 5px;">6</li><li style="box-sizing: border-box; padding: 0px 5px;">7</li><li style="box-sizing: border-box; padding: 0px 5px;">8</li><li style="box-sizing: border-box; padding: 0px 5px;">9</li><li style="box-sizing: border-box; padding: 0px 5px;">10</li><li style="box-sizing: border-box; padding: 0px 5px;">11</li><li style="box-sizing: border-box; padding: 0px 5px;">12</li><li style="box-sizing: border-box; padding: 0px 5px;">13</li><li style="box-sizing: border-box; padding: 0px 5px;">14</li><li style="box-sizing: border-box; padding: 0px 5px;">15</li></ul>

BEGIN模式

BEGIN模式是awk命令一种特殊的内置模式,在awk读取数据之前对执行的操作;

例如:

<code class="hljs livecodeserver has-numbering" style="display: block; padding: 0px; color: inherit; box-sizing: border-box; font-family: 'Source Code Pro', monospace;font-size:undefined; white-space: pre; border-radius: 0px; word-wrap: normal; background: transparent;"><span class="hljs-comment" style="color: rgb(136, 0, 0); box-sizing: border-box;">#! /usr/bin/awk -f</span><span class="hljs-comment" style="color: rgb(136, 0, 0); box-sizing: border-box;">#filename:test.sh</span>BEGIN { print <span class="hljs-string" style="color: rgb(0, 136, 0); box-sizing: border-box;">"Beging operator."</span> }/^<span class="hljs-constant" style="box-sizing: border-box;">one</span>/ , $<span class="hljs-number" style="color: rgb(0, 102, 102); box-sizing: border-box;">3</span>==<span class="hljs-number" style="color: rgb(0, 102, 102); box-sizing: border-box;">14</span> {print}<span class="hljs-comment" style="color: rgb(136, 0, 0); box-sizing: border-box;">#执行结果:</span>$ ./test.sh test.txtBeging operator.<span class="hljs-constant" style="box-sizing: border-box;">one</span>     <span class="hljs-number" style="color: rgb(0, 102, 102); box-sizing: border-box;">10</span>  <span class="hljs-number" style="color: rgb(0, 102, 102); box-sizing: border-box;">20</span>  <span class="hljs-number" style="color: rgb(0, 102, 102); box-sizing: border-box;">30</span><span class="hljs-constant" style="box-sizing: border-box;">two</span>     <span class="hljs-number" style="color: rgb(0, 102, 102); box-sizing: border-box;">15</span>  <span class="hljs-number" style="color: rgb(0, 102, 102); box-sizing: border-box;">25</span>  <span class="hljs-number" style="color: rgb(0, 102, 102); box-sizing: border-box;">20</span><span class="hljs-constant" style="box-sizing: border-box;">three</span>   <span class="hljs-number" style="color: rgb(0, 102, 102); box-sizing: border-box;">20</span>  <span class="hljs-number" style="color: rgb(0, 102, 102); box-sizing: border-box;">15</span>  <span class="hljs-number" style="color: rgb(0, 102, 102); box-sizing: border-box;">31</span><span class="hljs-constant" style="box-sizing: border-box;">four</span>    <span class="hljs-number" style="color: rgb(0, 102, 102); box-sizing: border-box;">16</span>  <span class="hljs-number" style="color: rgb(0, 102, 102); box-sizing: border-box;">26</span>  <span class="hljs-number" style="color: rgb(0, 102, 102); box-sizing: border-box;">35</span><span class="hljs-constant" style="box-sizing: border-box;">five</span>    <span class="hljs-number" style="color: rgb(0, 102, 102); box-sizing: border-box;">11</span>  <span class="hljs-number" style="color: rgb(0, 102, 102); box-sizing: border-box;">14</span>  <span class="hljs-number" style="color: rgb(0, 102, 102); box-sizing: border-box;">40</span></code><ul class="pre-numbering" style="box-sizing: border-box; position: absolute; width: 50px; top: 0px; left: 0px; margin: 0px; padding: 6px 0px 40px; border-right-width: 1px; border-right-style: solid; border-right-color: rgb(221, 221, 221); list-style: none; text-align: right; background-color: rgb(238, 238, 238);"><li style="box-sizing: border-box; padding: 0px 5px;">1</li><li style="box-sizing: border-box; padding: 0px 5px;">2</li><li style="box-sizing: border-box; padding: 0px 5px;">3</li><li style="box-sizing: border-box; padding: 0px 5px;">4</li><li style="box-sizing: border-box; padding: 0px 5px;">5</li><li style="box-sizing: border-box; padding: 0px 5px;">6</li><li style="box-sizing: border-box; padding: 0px 5px;">7</li><li style="box-sizing: border-box; padding: 0px 5px;">8</li><li style="box-sizing: border-box; padding: 0px 5px;">9</li><li style="box-sizing: border-box; padding: 0px 5px;">10</li><li style="box-sizing: border-box; padding: 0px 5px;">11</li><li style="box-sizing: border-box; padding: 0px 5px;">12</li><li style="box-sizing: border-box; padding: 0px 5px;">13</li><li style="box-sizing: border-box; padding: 0px 5px;">14</li><li style="box-sizing: border-box; padding: 0px 5px;">15</li><li style="box-sizing: border-box; padding: 0px 5px;">16</li></ul>

END模式

END模式是在处理完数据之后执行的操作;例如:

<code class="hljs asciidoc has-numbering" style="display: block; padding: 0px; color: inherit; box-sizing: border-box; font-family: 'Source Code Pro', monospace;font-size:undefined; white-space: pre; border-radius: 0px; word-wrap: normal; background: transparent;">#! /usr/bin/awk -f# /usr/bin/env awk -f#filename:test.shBEGIN {<span class="hljs-code" style="box-sizing: border-box;">    print "Beging operator."</span><span class="hljs-code" style="box-sizing: border-box;">    print "===================="</span>}/^one/ , $3==14 {print}END {<span class="hljs-code" style="box-sizing: border-box;">    print "===================="</span><span class="hljs-code" style="box-sizing: border-box;">    print "Ending operator."</span>}#执行结果:$ ./test.sh test.txt<span class="hljs-header" style="box-sizing: border-box;">Beging operator.====================</span>one     10  20  30two     15  25  20three   20  15  31four    16  26  35<span class="hljs-header" style="box-sizing: border-box;">five    11  14  40====================</span>Ending operator.</code><ul class="pre-numbering" style="box-sizing: border-box; position: absolute; width: 50px; top: 0px; left: 0px; margin: 0px; padding: 6px 0px 40px; border-right-width: 1px; border-right-style: solid; border-right-color: rgb(221, 221, 221); list-style: none; text-align: right; background-color: rgb(238, 238, 238);"><li style="box-sizing: border-box; padding: 0px 5px;">1</li><li style="box-sizing: border-box; padding: 0px 5px;">2</li><li style="box-sizing: border-box; padding: 0px 5px;">3</li><li style="box-sizing: border-box; padding: 0px 5px;">4</li><li style="box-sizing: border-box; padding: 0px 5px;">5</li><li style="box-sizing: border-box; padding: 0px 5px;">6</li><li style="box-sizing: border-box; padding: 0px 5px;">7</li><li style="box-sizing: border-box; padding: 0px 5px;">8</li><li style="box-sizing: border-box; padding: 0px 5px;">9</li><li style="box-sizing: border-box; padding: 0px 5px;">10</li><li style="box-sizing: border-box; padding: 0px 5px;">11</li><li style="box-sizing: border-box; padding: 0px 5px;">12</li><li style="box-sizing: border-box; padding: 0px 5px;">13</li><li style="box-sizing: border-box; padding: 0px 5px;">14</li><li style="box-sizing: border-box; padding: 0px 5px;">15</li><li style="box-sizing: border-box; padding: 0px 5px;">16</li><li style="box-sizing: border-box; padding: 0px 5px;">17</li><li style="box-sizing: border-box; padding: 0px 5px;">18</li><li style="box-sizing: border-box; padding: 0px 5px;">19</li><li style="box-sizing: border-box; padding: 0px 5px;">20</li><li style="box-sizing: border-box; padding: 0px 5px;">21</li><li style="box-sizing: border-box; padding: 0px 5px;">22</li><li style="box-sizing: border-box; padding: 0px 5px;">23</li><li style="box-sizing: border-box; padding: 0px 5px;">24</li><li style="box-sizing: border-box; padding: 0px 5px;">25</li><li style="box-sizing: border-box; padding: 0px 5px;">26</li><li style="box-sizing: border-box; padding: 0px 5px;">27</li><li style="box-sizing: border-box; padding: 0px 5px;">28</li></ul>

awk 变量

awk中的用户自定义的变量一般在BEGIN模式中定义;

系统内置变量

awk的常用系统内置变量如下表所示:

变量说明$0当前记录(存放着整个行的内容)$1~$n当前记录的第n个字段,字段间由FS分隔FS输入字段分隔符 默认是空格或TabNF当前记录中的字段个数,就是有多少列NR已经读出的记录数,就是行号,从1开始,如果有多个文件话,这个值也是不断累加中FNR当前记录数,与NR不同的是,这个值会是各个文件自己的行号RS输入的记录分隔符, 默认为换行符OFS输出字段分隔符, 默认也是空格ORS输出的记录分隔符,默认为换行符FILENAME当前输入文件的名字

运算符

awk命令支持常用的运算符:算术运算符、赋值运算符、条件运算符、逻辑运算法、关系运算符等操作;

算术运算符

awk命令直接支持的算术运算符有:加+、减-、乘*、除/、模运算%、指数运算^;

赋值运算符

awk命令常用的赋值运算符有:=、+=、-=、*=、/=、%=、^=;

条件运算符

awk命令的条件运算符语法如下所示:

<code class="hljs  has-numbering" style="display: block; padding: 0px; color: inherit; box-sizing: border-box; font-family: 'Source Code Pro', monospace;font-size:undefined; white-space: pre; border-radius: 0px; word-wrap: normal; background: transparent;">表达式?值1:值2</code><ul class="pre-numbering" style="box-sizing: border-box; position: absolute; width: 50px; top: 0px; left: 0px; margin: 0px; padding: 6px 0px 40px; border-right-width: 1px; border-right-style: solid; border-right-color: rgb(221, 221, 221); list-style: none; text-align: right; background-color: rgb(238, 238, 238);"><li style="box-sizing: border-box; padding: 0px 5px;">1</li></ul>

逻辑运算法

awk命令支持的逻辑运算符:&&、||、!;

关系运算符

awk命令支持的关系运算符:>、>=、<、<=、==、!=、~、!~;

awk 函数

awk提供了许多系统函数,用户也可以自定义函数;

字符串函数

常用的字符串函数有:

函数说明index(string1, string2)返回 string2 在string1中第一次出现的位置length(string)返回string的长度match(string,regexp)返回string中符合regexp的子字符串split(string,array,seperator)根据分隔符seperator,将字符串string分隔成多个字段,并存储到数组array中sub(regexp,replacement,string)将字符串string第一个符合regexp的子字符串替换成replacementgsub(regexp,replacement,string)将字符串string中符合regexp的全部子字符串都替换成replacementsubstr(string,start,[length])从字符串string的start位置开始截取长度为length(若指定了length,否则一直截取到字符串string结束)字串

算术函数

常用的算术函数有:int(x)、sqrt(x)、exp(x)、log(x)、sin(x)、cos(x)、rand(x)、srand(x);

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