Path variables are placeholders that stand for absolute paths to resources that are linked to your project but are stored outside it. If you are working in a team, these absolute paths on the computers of your teammates may differ. With path variables, you can flexibly share your code so all the references to the linked resources are resolved properly as the path variables accept the values according to the configuration on each specific computer.
In IntelliJ IDEA, there are some pre-defined variables:
$USER_HOME$: stands for your home directory.
$PROJECT_DIR$: stands for the directory where your project is stored.
$MODULE_DIR$: stands for the directory that keeps module configuration files IML.
To configure path variables, in the Settings/Preferences dialog Ctrl+Alt+S, select .
Create a new path variable
For example, you have a third-party library that is not stored in your project directory. If you want to make sure that the path is correct on your teammates' computers after they update the project from VCS, you can create a new variable.
Press Ctrl+Alt+S to open IDE settings and select Appearance & Behavior | Path Variables.
Click and enter the name of the new variable (for example,
PATH_TO_LIB) and its value that points to the library location on your disk.
Share the IML file through your version control system.
After your teammates update their projects from VCS, they will change the
PATH_TO_LIBvariable value so that it points to the library location on their computers.
Ignored path variables
When you open a project, IntelliJ IDEA checks if there are any unresolved path variables. If the IDE detects any, it will ask you to define values for them. If for some reason you don’t want to do that (for example, if you are not going to use files or directories with the unresolved path variables), you can add them to the list of ignored variables.
You can also use the list of ignored variables if, for example, a program argument passed to the JVM in a run/debug configuration has the same format as an internal
($SOME_STRING$) path variable. In this case, you can add this parameter to the list of ignored variables in order to avoid confusion. Enter
SOME_STRING to the Ignored Variables field in the Path Variables dialog.