Set global environment variables
/etc/profile
Initialized for login user shell only, any Bourne shell compatible can be used
/etc/bash.bashrc
Initialized only for interactive shells, bash supports
/etc/environment
Global environment variables, whether logged in or not, can be used, but the content can only be: key=value format, cannot be exported, cannot use variables, but pay attention to the startup sequence, maybe your program is executed before this, still cannot Get the variable set here