### 2.2.1 The Xcas interface

To run Xcas in a graphical environment, it depends on which operating system you are using.

- If you are using Unix, you can usually find an entry for the program in a menu provided by the environment. Otherwise, you can start it from a terminal by typing

  > xcas &

  If for some reason Xcas becomes unresponsive, you can open a terminal and type

  > killall xcas

  That will kill any running Xcas processes. When you restart Xcas, you will be asked if you want to resume where you left off using an automatic backup file.
- If you are running Windows, you can use the explorer to go to the directory where Xcas is installed. In that directory will be a file called xcas.bat. Clicking on that file will start Xcas.
- If you are running Mac OS, you can use the Finder to go to the xcas_image.dmg file and double-click it. Then double-click the Xcas disk icon. Finally, to launch Xcas, double-click the Xcas program.

When you start Xcas, a window will pop up with menu entries across the top, a bar indicating information about the current Xcas configuration, and an entry line you can use to enter commands. This interface will be described in more detail later, and you can get help from within Xcas with the menu item

Help▸Interface