Bash shell 字符串

Sunday, Apr 28, 2019 | 2 minute read | Updated at Sunday, Apr 28, 2019

@ Cai Song

字符串常用操

拼接直接拼接
```
echo "$str1$str2"
```

查找

运算符

[[ $str3 =~ $str1 ]]

通配符

[[ $str3 == *$str2 ]] #以str2结尾
[[ $str3 == $str1* ]] #以str1开头

case

case $str3 in 
  HELLO)  echo "cai" ;;
  H*O) echo "song" ;;
  *) echo "caisong" ;;
esac

替换

#语法：${变量/查找/替换值}
# 若查找字符前以'//'开头则全部替换
${str1/$str2/$str3}

长度
```
echo ${#str}
```

切割

cut

  echo $str|cut -d'-' -f2

IFS

#IFS指定分隔符
OIFS=$IFS;IFS='-';set -- $str; str1=$1;str2=$2;IFS=$OIFS;

截取

从头部截取指定字符

# 语法：
${varibale#*string} #截取第一个string后的字符
${varible##*string} #截取最后一个string后的字符

从尾部截取指定字符

# 语法：
${varibale%string*} #截取第一个string后的字符
${varible%%string*} #截取最后一个string后的字符

示例

#!/bin/bash

lyric1="Soft kitty, warm kitty, little ball of fur"
lyric2="Happy kitty, sleepy kitty, purr, purr, purr"

echo -e $lyric1
echo -e $lyric2

echo -e "示例：拼接"
echo -e \\t "$lyric1 $lyric2"

echo -e "示例：查找"
echo -e "\t 1. 包含"
[[ $lyric1 =~ "kitty" ]] && echo -e "\t The lyric include kitty"

echo -e "2. 以字符串开头"
[[ $lyric1 == Soft*  ]] && echo -e "\t The lyric starts with 'Soft'"

echo -e "3. 以字符串结尾"
[[ $lyric2 == *purr ]] && echo -e \\t "The lyric ends with 'purr'"

echo -e "4. 使用case查找"
case $lyric1 in
    *ball)
        echo -e "\tThe lyric include ball" ;;
    sleepy*)
        echo -e "\tThe lyric include sleepy" ;;
    *kitty*)
        echo -e "\tThe lyric include kitty" ;;
esac

echo -e "示例：替换"
echo -e \\t ${lyric1/kitty/doraemon}
echo -e \\t ${lyric1//kitty/doraemon}


echo -e "示例：长度"
echo -e "\tThe length of lryic is $((${#lyric1}+${#lyric2}))"

echo -e "示例：切割"
echo -e "\tcut命令切割"
echo -e $lyric1 | cut -d',' -f1

echo -e "\tIFS切割"
OIFS=$IFS;IFS=',';set -- $lyric2;cat1=$1;cat2=$2;IFS=$OIFS
echo -e "\tThe two cats:" $cat1 $cat2

echo -e "示例：截取"
echo -e "1. 从开头截取最少匹配"
echo -e \\t ${lyric1#*kitty}
echo -e "2. 从开头截取最多匹配"
echo -e \\t ${lyric1##*kitty}

echo -e "1. 从结尾截取最少匹配"
echo -e \\t ${lyric2%kitty*}
echo -e "2. 从结尾截取最多匹配"
echo -e \\t ${lyric2%%kitty*}

输出

Soft kitty, warm kitty, little ball of fur
Happy kitty, sleepy kitty, purr, purr, purr
示例：拼接
         Soft kitty, warm kitty, little ball of fur Happy kitty, sleepy kitty, purr, purr, purr
示例：查找
         1. 包含
         The lyric include kitty
2. 以字符串开头
         The lyric starts with 'Soft'
3. 以字符串结尾
         The lyric ends with 'purr'
4. 使用case查找
        The lyric include kitty
示例：替换
         Soft doraemon, warm kitty, little ball of fur
         Soft doraemon, warm doraemon, little ball of fur
示例：长度
        The length of lryic is 85
示例：切割
        cut命令切割
Soft kitty
        IFS切割
        The two cats: Happy kitty sleepy kitty
示例：截取
1. 从开头截取最少匹配
         , warm kitty, little ball of fur
2. 从开头截取最多匹配
         , little ball of fur
1. 从结尾截取最少匹配
         Happy kitty, sleepy
2. 从结尾截取最多匹配
         Happy

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