Installing Release 12.1 on UNIX Workstations (MATLAB Installation Guide for Unix) MATLAB Installation Guide for Unix     Saving Your MATLAB Environment When you install a new product, the installer regenerates your path file, pathdef.m, and your printing and documentation preference files, printopt.m and docopt.m, respectively. The installer does not delete the your existing path or preferences files; instead it renames them to pathdef.old, printopt.old, and docopt.old, in the same directory ($MATLAB/toolbox/local). To reuse your previous path file or preferences file, rename the saved version of the file, replacing the .old extension with the .m extension. To save copies of the new versions of these files, rename them. For example, to use your previous path file, use this code. cd $MATLAB/toolbox/local mv pathdef.m pathdef.new mv pathdef.old pathdef.m When reusing an old pathdef.m file, you may need to add any new products that you just installed.  Installing Additional Products Managing Your Licenses