Description: Environment variables in operating systems are dynamic values that can influence the behavior of running processes. These variables act as configurations that the system and applications can use to determine how they should execute. For example, they can define the working directory, language settings, executable file search paths, and other parameters that affect program execution. Environment variables are fundamental for personalizing the user’s working environment and for configuring applications, allowing different users and processes to operate efficiently and tailored to their specific needs. They can be set temporarily in a terminal session or permanently in configuration files, depending on the system. The ability to modify these variables allows users and system administrators to optimize their experience and system performance, making environment variables an essential tool in system administration.
History: Environment variables have their roots in Unix operating systems, which were developed in the 1970s. Over time, as Linux gained popularity in the 1990s, environment variables became a standard feature in this operating system, inheriting functionality from Unix. Over the years, their use has expanded and evolved, adapting to the needs of users and developers.
Uses: Environment variables are used to configure the behavior of applications and scripts, define paths to files and directories, and set user-specific configurations such as language and time zone. They are also essential for running programs in different environments, such as development, testing, and production.
Examples: An example of an environment variable is ‘PATH’, which defines the paths where the system looks for executables. Another example is ‘HOME’, which indicates the user’s home directory. The ‘LANG’ variable can also be set to define the system’s language.
