# Setting Up the “gaffer” Command¶

After you have installed Gaffer, it will remain a collection of files and directories on your file system. Because it is not yet configured as a command, you must navigate to its directory every time. This could become very tedious, so we recommend that you modify your PATH environment variable to allow access to the gaffer command from anywhere in the terminal.

Note

For these instructions, we will assume you have Gaffer installed to the /opt/ directory. If you have installed it elsewhere, replace /opt/ with the directory you installed it to.

## Environment variables¶

An environment variable is simply a value, such as a string, number, boolean, or location that your terminal is aware of. For instance, when you ran the tar command to extract the downloaded Gaffer package, the tar command was not located in your ~/Downloads directory, but actually in /usr/bin/. Whenever you open your terminal, several folders are added to your terminal’s PATH environment variable, which provides it with a list of locations in the file system from which it can source commands.

In order for the gaffer command to work in your terminal, you will need to add Gaffer’s directory to the PATH environment variable.

## Setting up the “gaffer” command in Linux¶

The particular terminal on your system depends on your Linux distribution and how it was configured. Most distributions of Linux use bash, but there are other common terminals available, like tcsh. Because we cannot accommodate every available terminal, we will only provide instructions for adding to the PATH variable in bash and tcsh.

Tip

If you are not sure which terminal you have, you can find its name by opening a terminal and inputting echo $0, which will return /bin/bash, tcsh, or some equivalent. If you are not using bash or tcsh, the same principles of environment variables will apply, and your terminal’s documentation should provide a comparable way of modifying the PATH variable. To set up the gaffer command in Linux: 1. Open your terminal’s config file in a text editor. • bash config: ~/.bash_profile • tcsh config: ~/.tcsh_profile 2. Add the following line to the end of the file: • bash: export PATH=$PATH\:/opt/gaffer-0.55.0.0-linux/bin
• tcsh: setenv PATH $PATH\:/opt/gaffer-0.55.0.0-linux/bin 3. Save the file. 4. Open a terminal. 5. Test that the PATH variable has been updated: user@desktop ~$ echo $PATH # /usr/local/bin:/usr/bin:/bin:/opt/gaffer-0.55.0.0-linux/bin  Note Depending on your system configuration, the beginning of your PATH variable might not appear exactly as above. What’s important is whether /opt/gaffer-0.55.0.0-linux/bin appears at the end of the path. You can now execute gaffer as a command from any directory in the terminal. ## Setting up the “gaffer” command in OSX¶ The default terminal in OSX is bash, so you will need to add to the PATH variable in the bash user config. To set up the gaffer command in OSX: 1. Open ~/.bash_profile in a text editor. 2. Add the line export PATH=$PATH\:/opt/gaffer-0.55.0.0-osx/bin and save.

3. Open the terminal (Finder > Go > Utilities > Terminal).

4. Test that the PATH variable has been updated:

MacBook:~ user$echo$PATH
# /usr/bin:/bin:/usr/sbin:/sbin:/usr/local/bin:/opt/X11/bin:/opt/gaffer-0.55.0.0-osx/bin


Note

Depending on your system configuration, the beginning of your PATH variable might not appear exactly as above. What’s important is whether /opt/gaffer-0.55.0.0-osx/bin appears at the end of the path.

You can now execute gaffer as a command from any directory in the terminal.

## Using the “gaffer” command¶

Once you have added the Gaffer directory to the PATH variable, you can launch Gaffer anywhere in the terminal:

gaffer


You can also use the command to open Gaffer scripts, as outlined in the Command Line Reference.