The environment variable ABACUS_DIR has to be set to the directory containing the general configuration file .abacus. A master version of this configuration file is provided in the base directory of the ABACUS distribution. It is recommended that every user makes a private copy of the file .abacus and sets ABACUS_DIR accordingly.
To set the environment variable to /home/yourhome, for example, using the C-shell or its relatives, do:
setenv ABACUS_DIR /home/yourhome
If the Bourne-shell is used do:
export ABACUS_DIR=/home/yourhome
Usually it is convenient to add these instructions to the personal .login file.