The PATH variable

    What is the “PATH”? #

    If you have been following the lessons and help guides available on this website, and installing software such as FFmpeg and AP (AnalysisPrograms) then you have probably seen the term PATH by now.

    The PATH variable is an environment variable. Environment variables are values that any program can access. The PATH variable contains a list of folders that your computer can check when it searches for programs to run.

    In simple terms, if we want to use a program in a terminal (see the terminal basics guide), we have two choices. We can specify the full path to the program (often referred to as a binary, usually has an extension like .exe on Windows) file, and then write our code:

    > C:\Users\Anthony\AP\AnalysisPrograms.exe 

    > ~/AP/AnalysisPrograms

    But this would be annoying to write out every time. Instead, if our PATH variable includes the AP folder, we can run AP commands without specifying this full path!

    > AnalysisPrograms.exe

    > AnalysisPrograms

    How to check the PATH variable #

    We can quickly check if a program has been successfully added to our PATH or not. Open up a terminal and type a command for the program we are interested in testing.

    > FFmpeg

    If the command successfully returns some kind of output about the package, then it is available on your PATH.

    You can check the list of folders contained in your PATH variable using printenv PATH in Bash, echo $env:Path in PowerShell, and printenv PATH in Zsh. If the folder where you installed a program you want to use is not listed, then you may need to add it to the PATH.

    Adding to PATH #

    If you use a package manager such as chocolatey on Windows, homebrew on macOS or snap on Linux, then packages you install with those commands should be automatically added to your PATH variable. This saves you having to manually change the PATH variable. The automatic installer for AP will also automatically add AP to PATH for you.

    If you need to add a program to the PATH manually, you can follow these steps:

    1. Find where the program is installed on your computer. This will be a directory (folder) where the .exe resides.
    2. Open your System Environment Variables. You can type some of “Edit environment variables for your account” in the Start Menu search box to find the settings.
    3. Choose Environment Variables… in the windows that popped up
    4. In the user variables section, find the Path variable, select it, and then hit the Edit button
    5. Add the directory from step 1 to the end
    • Ensure a semi-colon (;) delimits the new directory from the previous ones, if you’re using an older version of Windows
    1. Then click OK or close all windows.
    2. You will have to restart any programs for which you want to see the new value

    Note: If you are using PowerShell, you could instead run $env:Path=$env:Path;<REPLACE-ME> to add a directory to your PATH

    1. Find where the program is installed on your computer. This will be a directory (folder) where the binary resides.
    2. Check whether your terminal is using Bash or Zsh shell
      • For Bash: open or create your ~/.profile file
      • For Zsh: open or create your ~/.zshrc file
    3. Add the following line to the end:

    PATH=$PATH:<REPLACE-ME>

    Where you replace the <REPLACE-ME> with the directory from step 1.

    1. Close and save the file
    2. Run the same command in your current shell (PATH=$PATH:) to see the change take effect immediately (or restart your shell).
    1. Find where the program is installed on your computer. This will be a directory (folder) where the .exe resides.
    2. Open or create your ~/.profile file
    3. Add the following line to the end:

    PATH=$PATH:<REPLACE-ME>

    where you replace the <REPLACE-ME> with the directory from step 1.

    1. Close and save the file
    2. Run the same command in your current shell (PATH=$PATH:) to see the change take effect immediately (or restart your shell).