Linux: permanently update your PATH.

To permanent change your PATH:

1. Locate your profile file. This is your user-specific initialization file for your shell and you can find it in the root of your home directory (~). It can be named slightly differently depending on your distribution and the type of shell you are using (.bash_profile, .zprofile, etc.), but it's really not easy to miss. In my case (Fedora & bash), my profile file is named .bash_profile.
2. Make desired changes to your PATH. There's a good chance the file already has some PATH changes, so just append yours.
   
   

   # .bash_profile
   
   # Get the aliases and functions
   if [ -f ~/.bashrc ]; then
    . ~/.bashrc
   fi
   
   # User specific environment and startup programs
   
   PATH=$PATH:$HOME/.local/bin:$HOME/bin
   PATH=$PATH:~/Documents/rebar3
   
   export PATH
   

   
   
3. Now for the changes to take effect you can either simply log out and log back in or run:
   
   

   source ~/.bash_profile
   

   
   That will basically execute the command defined in ~/.bash_profile using your current shell.

And that's it.

Thank you and happy hacking!

Piotr