All basic Linux commands fail, for example -bash: ll: command not found

Problem scenario:

After installing the program in the Linux environment, after configuring the environment variables and source /etc/profile, a problem occurs.

Cause Analysis:

This happens because after the environment variable is configured, the inherited $PATH environment variable is missing

However, since all basic commands are invalid, it is impossible to re-enter the etc/profile file for modification.

problem solved:

Type in the console:

export PATH=/usr/bin:/usr/sbin:/bin:/sbin:/usr/X11R6/bin

You can restore the use of basic commands, and then enter the directory of the environment variable to modify it.