$PATH is the environment variable related to Linux Path settings.
To add a directory to the path, type
$ export PATH=$PATH:/tmp/myshells
The above change is in effect only in the shell from where it is being called
To set the PATH for a specific user, type the below 2 lines in the user’s .bash_profile file ($HOME/.bash_profile).
To set the PATH for ALL users except the root user, type the following line in /etc/profile
Root user is not affected by any setting changes under /etc/profile. To set the path for the root user, we need to modify the root users’ .bash_profile (/root/.bash_profile)