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

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

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