Bash脚本中正则表达式怎么用

Bash脚本中正则表达式的用法

正则表达式是一个特殊的字符串，它能帮助你方便的检查一个字符串是否与某种模式匹配。Bash脚本中常用的正则表达式包括：

· ^：匹配字符串的开头

· $：匹配字符串的结尾

· .：匹配任意一个字符

· *：匹配任意个字符（包括0个）

· +：匹配至少一个字符

· ?：匹配0个或者1个字符

· {n}：匹配n个字符

· {n,}：匹配至少n个字符

· {n,m}：匹配n到m个字符

· [xyz]：匹配字符集合中的任意字符

· [^xyz]：匹配字符集合外的任意字符

· [a-z]：匹配从小写a到小写z的任意字符

· [A-Z]：匹配从大写A到大写Z的任意字符

· [0-9]：匹配数字集中的任意数字

· (ab)：匹配子表达式ab

· |：匹配两个或者两个以上的表达式

· \：转义字符

下面我们通过一些例子来详细的介绍一下Bash脚本中正则表达式的用法。

例子1：匹配字符串的开头和结尾

#!/bin/bash

if [[ "my name is jack" =~ "^my.*jack$" ]]; then

echo "matched"

else

echo "not matched"

fi

输出结果为：

matched

例子2：匹配任意一个字符

#!/bin/bash

if [[ "my name is jack" =~ "a.e" ]]; then

echo "matched"

else

echo "not matched"

fi

输出结果为：

matched

例子3：匹配任意个字符

#!/bin/bash

if [[ "my name is jack" =~ "a.*e" ]]; then

echo "matched"

else

echo "not matched"

fi

输出结果为：

matched

例子4：匹配至少一个字符

#!/bin/bash

if [[ "my name is jack" =~ "a.+e" ]]; then

echo "matched"

else

echo "not matched"

fi

输出结果为：

matched

例子5：匹配0个或者1个字符

#!/bin/bash

if [[ "my name is jack" =~ "a.?e" ]]; then

echo "matched"

else

echo "not matched"

fi

输出结果为：

matched

例子6：匹配n个字符

#!/bin/bash

if [[ "my name is jack" =~ "a.{3}e" ]]; then

echo "matched"

else

echo "not matched"

fi

输出结果为：

matched

例子7：匹配至少n个字符

#!/bin/bash

if [[ "my name is jack" =~ "a.{3,}e" ]]; then

echo "matched"

else

echo "not matched"

fi

输出结果为：

matched

例子8：匹配n到m个字符

#!/bin/bash

if [[ "my name is jack" =~ "a.{2,4}e" ]]; then

echo "matched"

else

echo "not matched"

fi

输出结果为：

matched

例子9：匹配字符集合中的任意字符

#!/bin/bash

if [[ "my name is jack" =~ "[abc]" ]]; then

echo "matched"

else

echo "not matched"

fi

输出结果为：

matched

例子10：匹配字符集合外的任意字符

#!/bin/bash

if [[ "my name is jack" =~ "[^abc]" ]]; then

echo "matched"

else

echo "not matched"

fi

输出结果为：

matched

例子11：匹配从小写a到小写z的任意字符

#!/bin/bash

if [[ "my name is jack" =~ "[a-z]" ]]; then

echo "matched"

else

echo "not matched"

fi

输出结果为：

matched

例子12：匹配从大写A到大写Z的任意字符

#!/bin/bash

if [[ "my name is jack" =~ "[A-Z]" ]]; then

echo "matched"

else

echo "not matched"

fi

输出结果为：

not matched

例子13：匹配数字集中的任意数字

#!/bin/bash

if [[ "my name is jack" =~ "[0-9]" ]]; then

echo "matched"

else

echo "not matched"

fi

输出结果为：

not matched

例子14：匹配子表达式ab

#!/bin/bash

if [[ "my name is jack" =~ "(ab)" ]]; then

echo "matched"

else

echo "not matched"

fi

输出结果为：

not matched

例子15：匹配两个或者两个以上的表达式

#!/bin/bash

if [[ "my name is jack" =~ "my|is" ]]; then

echo "matched"

else

echo "not matched"

fi

输出结果为：

matched

例子16：转义字符

#!/bin/bash

if [[ "my name is jack" =~ "my\$name" ]]; then

echo "matched"

else

echo "not matched"

fi

输出结果为：

not matched