In ISE Design Suite12.x and later, most Xilinx tools will launch a boot loader script to set up the correct environment before launching the actual executable. However, a user may want to ensure that the required $Xilinx and other environment variables are set prior to running.
WithISE Design Suite 12.xand later or Vivado2012.2 and later installs,the Installer creates settings32 or settings64.bat files or settings32 or settings64.sh files (depending onthe system OS), instead of setting the global environment variables. These batch/script files contain all the environment settings the Installer previously set globally (11.1).
Example: If you open a normal Windows command shell, you can run the settings batch file from the Xilinx installation you want to use (i.e., C:\Xilinx\12.3\ISE_DS\settings32.bat). In this example, it would set $Xilinx and other related variables to point to your 12.3 installation. This file only has to be run once per DOS shell window.
For your convenience, a shortcut to a DOS shell window is provided with the environment already set:
If you need to run Windows-based Xilinx implementation script, the settings batch file should be referenced in the script before any Xilinx command-line implementation tools are invoked. See (Xilinx Answer 35789) for details.