- HOME - user's home directory. This variable is equivalent with `~'.
- TUCNAK - directory to store tucnak informations. Normally $HOME/tucnak. Precedence over HOME
- TUCNAK_DEBUG - if this variable is set then debug information is written to stderr. If you can define file name to save debug information you must refill this variable.
Read for minor reasons: COLORTERM, COLUMNS, DISPLAY, LANG, LC_*, LINES, SHELL, STY, TEMP, TERM, TMP, TWDISPLAY, USER