  ++ E N V I R O N M E N T   V A R I A B L E S ++

Q acts on the following environment variables:-

1. SHELL determines what shell is used to implement the "!" command.
   Default if absent: /bin/sh
2. Q_HELP_DIR says where the help files are.
   Default if absent: /usr/local/share/q
3. Q_MACRO_DIR says where the standard Q macros are.
   Default if absent: same as help dir. Q is distributed that way
4. Q_HELP_CMD is the command to use to display help files.
   Default if absent: use PAGER environment variable.
   Default if neither PAGER nor Q_HELP_CMD in environment: "less"
