Summary of the operation of shell script and vi

(1) Tab prompt

(2) Set the language of the text: set fileformat=unix or set ff =unix

(3) Set the read, write and execute permissions of the file: chmod 777 file name (777 is all permissions)

(4) The end of an if in the shell script is that fi must be marked, otherwise an error will be reported

(5) Check whether the firewall on linux is open: systemctl status firewalld