If you are slightly familiar with programming, then you know what variables are. Variables are symbols that contain a value, which is usually a text or number. The variables that are part of the system and environment variables are used to operate it. Every operating system has environment variables.
Environment variables are related to the test and give us details about the environment in the form of variables. Here the details of the test include details about the operating system, the version, the folder on which it resides, and where the results reside. It gives all the information about the environment of that test. Hence, the name environment variables.
Each variable has a name and a value. The names are all uppercase and the values are strings. Environment variables are used to communicate with the programs, set up the machines, and even control the behaviour of the program.
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Why Are Environment Variables So Important?
You can use environment variables to configure your system, program, and pipeline. Most CG software such as composites or 3D software inherit the different types of environment variables and give you access to use these variables at a system level. These variables can also help you to write flexible software.
Instead of hard coding a value, you can set up an environment variable and as long as it is set up there, you can change the variable and the script of the program will change accordingly.
If you are on Linux or macOS, you can simply open your terminal and type “env”. This will pop up a window filled with variables, and this is referred to as the environment.
If you are on Windows, you can use the advanced system settings on the control panel to find your environment variables.
How to Use Environment Variables?
Environment variables or .env files. Since .env files are used to store command lines and sensitive information such as credentials for apps or software, they should not be seen by the end-users.
Few examples of environment variables are database credentials, API endpoints, and API keys. These variables are also going to be environment-specific. So if your program is running in a different environment, then some of these data will change depending on the environment.
Here are a few ways to use environment variables
1. For Software Configuration
Some applications offer their users more flexibility and allow them to specify the different locations where a plug-in or script might live. This way, users can manage their assets better and do not need to move all the information into a single folder.
Older software used to have one single folder for the plug-ins, and one had to put the plug-ins in that single folder to make them work. However, this makes things difficult because you would want the core of the program to be as it is with little human interaction in its original location.
This can be done easily with environment variables. You can use PLUG_IN_PATH, SCRIPT_PATH, or for finding scripts, destination, initialization, and configuration files. You can use LM_LISCENCE_FILE to dictate the location of the license and OTL_PATH to save the location of your operating type library.
2. For Pipeline Configuration
The pipeline is also referred to as a data pipeline, where the result of one element is the input for the next one. It is a series of data processing units. Environment variables can be used to configure pipelines and make the process easier.
Developers can use environment variables such as DEPT, SEQ, SHOT, SHOW to configure a system, output directories, software configuration, plug-in paths, and other types of values.
This creates a contextual environment so that before starting an application or program we have to set up our department, sequence, and the shot. This simplifies the process and output destination. You do not have to worry about setting up a different output folder or accidentally sending it to the wrong folder.
For example, let’s say you are working on a program named studio, you can create an environment variable naming
SHOW=/projects/show1
Now, you can create a SCRIPT_PATH variable with /studioScripts:$SHOW/shared/studio/scripts
This script path is now set to Studio scripts, which means all the scripts that are part of the Studio will be in this script path. First, it will open a bunch of studio scripts, and then it will load the local scripts for the current show.
Now if you have two scripts with the same name where one is at the studio script, then changes in the other script will override the information of the studio script. The overall process makes pipeline configuration less time-consuming and easy. You can do the same with plug-ins.
3. For Software and Script Flexibility
You can use variables such as USER and HOSTNAME to create log data. This is necessary for creating a script that allows the users to publish meshes into the pipeline.
Here, you can use the USERNAME and the HOSTNAME to conduct a “Date Lookup” and store log entries. This will keep records and a clear track of the source of information or access. This also helps the pipeline by informing from whom, what, and where the data is coming.
You can also use environment variables to reconfigure data. By using the variable called Show Config to point it to a JSON file with a bunch of settings and configure it with just the original variable “Show Config”.
4. For Setting Permanent Variables
In UNIX, depending on which terminal you use, you will have files named profile, .rclogin, or .bashrc, and these files are read in sequence. So if you are using bash, it will first load several files and then go to the user’s home directory to look for .bashrc.
So if you go to your home directory and type ls. bashrc and enter, you will see many different configuration files. You can now go to the export folder and make this your permanent variable.
Final Thoughts
You can easily configure your programs with the help of different environment variables. This takes the load off of hard coding and allows you to change groups of variables using one single source. This also makes your program user-friendly and secure.
