shell 字符串包含关系

# 方法1 ―― 字符比较[html]view plaincopyprint?#!/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
[html]view plaincopyprint?#!/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 ： includeecho "hello world" | grep -q "world " && echo "include" || echo "not include" # result ： not include

#方法4
[html]view plaincopyprint?#!/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 ： includeawk '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.txtbird
birds
angrybird
angrybirds
angry bird
angry birds
angry birds war

grep.sh
[html]view plaincopyprint?#!/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

原文链接：http://blog.csdn.net/sunboy_2050/article/details/8448871