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

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

参考推荐：

shell 判断字符串是否存在包含关系

Shell expr的用法

awk 实例

linux awk 内置函数详细介绍（推荐）

Linux 之 shell 比较运算符