m0_49022699的博客

变量:-word 如果变量为空则返回word子串 ，非空返回变量本身 zxh@zxh-virtual-machine:~$ echo $name zxh@zxh-virtual-machine:~$ # ${变量:-word}如果变量值为空返回word子串，非空返回变量 zxh@zxh-virtual-machine:~$ echo ${name:-zxh} zxh zxh@zxh-virtual-machine:~$ echo $name zxh@zxh-virtual-machine:~$ na

shell编程对于字符串的一些基础操作