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：