The following shell variables must be set appropriately for the tools to run properly:
| Variable Name | Use |
| CDS_INST_DIR | Cadence tools installation directory |
| LM_LICENSE_FILE | License files |
| PATH | Directories of the executables |
| LD_LIBRARY_PATH | Tool Shared libraries (if req.) |
| MANPATH | Tool manpages |
| SNPSLMD_LICENSE_FILE | Synopsys license file |
Each user can write their own start-up script for initialising all of these variables. Generic shell scripts for doing this are provided with some of the tools. For Cadence and Synopsys these are /vlsi/usr/cds4.43/IC/cshrc and /vlsi/usr/synopsys2000.05/cshrc respectively.