The GetEnvironmentVariable String method retrieves an environment variable from the environment block of the current process only. To retrieve all environment variables along with their values, call the GetEnvironmentVariables method. Environment variable names are case-sensitive on Linux and macOS but are not case-sensitive on Windows. All environment variables that are provided to it by the parent process that created it.
For example, a. NET application launched from a console window inherits all of the console window's environment variables.
If there is no parent process, per-machine and per-user environment variables are used instead. For example, a new console window has all per-machine and per-user environment variables defined at the time it was launched.
These environment variables persist until the. NET application terminates. If environment variables are created after the process has started, you can use this method to retrieve only those variables that were created by calling the SetEnvironmentVariable String, String method or the SetEnvironmentVariable String, String, EnvironmentVariableTarget method with a target value of. On macOS and Linux, the environment block of the current process includes the following environment variables:.
NET applications launched from a shell, this includes all environment variables defined in the shell. One of the EnvironmentVariableTarget values. Logon server is used to authenticate the user to login a system. In active directory system user credentials are authenticated in these authority servers. Path variable is used to find executable files. Path variable stored more than one path and if a command is issued these path are checked for this command executables to run. Windows operating system stores built-in and 3 party applications files and folder in Program Files directory.
This directory path can be printed like below. Windows operating system files, folders and libraries are stored in System Root and this root directory generally named windows. The PC user can also modify the contents using methods discussed further on. Adding directories to PATH can be very useful if you use scripts or the command line for system maintenance.
For example, it can be convenient to put the directory where you keep backups into the PATH variable. It can also be useful to modify PATH if you put programs in a directory different from the usual one. Note that the directory names are separated by a semicolon in the command statement.
An alternate form omits the "equals" sign. This command will replace any previous directories that were in the PATH variable. It is essential to remember that any changes that are made in a command window only endure until the window is closed. For permanent changes, use the method discussed in another section.
It is also possible to use the command-line executable setx. Any file that is in a directory listed in the PATH variable can be found or opened by direct reference to the name of the file without having to specify the drive and directories where it is located.
This is very handy in scripting and in other ways. For instance, the name of an executable file that is in a directory listed in the PATH variable can be entered into Start-Run to open certain applications more on this subject here. The file is sol. Normally this entire string would have to be used in order to reference the Solitaire game.
Because its directory is listed in the PATH variable, however, it is sufficient to reference just the file name sol. As is explained on other pages , file extensions tell Windows what it is supposed to do with a file.
Certain file extensions indicate that the file is executable ; that is, the file opens a program or does something. The extension. EXE is the most common. Thus the filename sol. If files have the same name but different extensions, the operating system searches in the following order of precedence:.
Greg Shultz is a freelance Technical Writer. Previously, he has worked as Documentation Specialist in the software industry, a Technical Support Specialist in educational industry, and a Technical Journalist in the computer publishing industry. To see a complete list of the environment variables that are active on a Windows XP system, follow these steps: Open a Command Prompt window.
Type Set and press [Enter]. CD: Lists the current directory string. DATE: Lists the current date.
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