shell 字符串包含关系

# 方法1 —— 字符比较

#!/bin/bash

str1="hello"
str2="he"
str3="lo"

if [ ${str1:0:2} = $str2 ]; then
    echo "$str1 include $str2"
fi

if [ ${str1:2:4} = $str3 ]
then
    echo "$str1 include $str3"
else
    echo "$str1 not include $str3"
fi

运行结果：

hello include he
hello not include lo

# 方法2 —— grep匹配

#!/bin/bash

str1="hello world"
str2="he"
str3="world "

echo "$str1" | grep -q "$str2"
if [ $? -eq 0 ]; then
    echo "$str1 include $str2"
fi


echo "$str1" | grep -q "$str3"
if [ $? -eq 0 ]; then
    echo "$str1 include $str3"
else
    echo "$str1 not include $str3"
fi

运行结果：

hello world include he
hello world not include world 

#方法3 —— 由方法2演变
echo "hello world" | grep -q "he" && echo "include" || echo "not include"           # result ： include

echo "hello world" | grep -q "world " && echo "include" || echo "not include"          # result ： not include

 

 

#方法4

#!/bin/bash

str1="hello world"
str2="he"
str3="world "


[[ "${str1/$str2/}" != "$str2" ]] && echo "include" || echo "not include"


[[ "${str1/$str2/}" != "$str2" ]]
if [ $? -eq 0 ]; then
    echo "$str1 include $str2"
fi

运行结果：

include
hello world include he

#方法5 —— expr 命令

expr有模式匹配功能，可以通过指定冒号选项计算字符串中字符数，.* 即任何字符重复0次或多次

expr 计算字符数：

expr  "accounts.doc" : '.*'          # result ： 12

expr 截取字符串

expr "accounts.doc" : '(.*).doc'         # result ： accounts

expr substr "hello world" 1 7              # result ： hello w

expr index "hello world" w                 # result ： 7

expr 截取数字

expr "string in 123 line" : '.*in (.*)'                # result ： 123 line

expr "string in 123 line" : '.*in (.*)line'           # result ： 123

expr "http://192.168.1.100/platform_example/branch/demo_platform is at revision 81" : '.*at revision (.*)'         # result： 81

substr 和 index 配合使用：

expr substr "hello world" 1 $(expr index "hello world" w)            # result ： hello w

#方法6 —— awk的index函数

awk 'BEGIN{info="this is hello world"; print index(info, "hello") ? "include" : "not include";}'            # result ： include

awk 'BEGIN{info="this is hello world"; print index(info, "helo") ? "include" : "not include";}'             # result ： not include

${var#...}                  
${var%...}
${var/.../...}

 

grep 精确匹配

1） echo "hello hellos hell" | grep hell               # result  ：  hello    hellos   hell

2） echo "hello hellos hell" | grep -w hell          # result  ：  hello    hellos   hell

3） echo "hello hellos hell" | grep "<hell>"      # result  ：  hello    hellos   hell

1） 模糊匹配； 2） 单词匹配； 3） 正则域匹配； 推荐方式3）

完整示例：

test.txt

bird
birds
angrybird
angrybirds
angry bird
angry birds
angry birds war

grep.sh

#!/bin/bash

cat test.txt

echo
echo "grep bird test.txt..."
grep birds test.txt

echo
echo "grep -w bird test.txt..."
grep -w birds test.txt

echo
echo "grep "<birds>" test.txt..."
grep "<birds>" test.txt

运行结果：

bird
birds
angrybird
angrybirds
angry bird
angry birds
angry birds war


grep bird test.txt...
birds
angrybirds
angry birds
angry birds war


grep -w bird test.txt...
birds
angry birds
angry birds war


grep <birds> test.txt...
birds
angry birds
angry birds war