Shell 字符串

字符串

字符串可以用单引号，也可以用双引号，也可以不用引号。

单引号:

• 单引号里的任何字符都会原样输出，包含变量。
• 单引号字串中不能出现单独单引号（对单引号使用转义符后也不行），但可成对出现，作为字符串拼接使用。

 #!/bin/bash

name='LiLei'
echo 'My name is '$name
echo 'My name is $name'
echo 'My name is ''LiLei'

#sh test.sh
My name is LiLei
My name is $name
My name is LiLei

双引号:

• 双引号里可以有变量
• 双引号里可以出现转义字符
• 双引号可作为字符串拼接使用

#!/bin/bash

name='LiLei'
echo "My name is "$name
echo "My name is $name"
echo "My name is '$name'"
echo "My name is \"$name\""
echo "My name is ""LiLei"

#sh test.sh
My name is LiLei
My name is LiLei
My name is 'LiLei'
My name is "LiLei"
My name is LiLei

计算字符串长度

记得加大括号{}

#!/bin/bash

name='LiLei'
echo ${#name}

#sh test.sh
5

字符串切片

#!/bin/bash

name='LiLei'
echo ${name:2:4}

#sh test.sh
Lei