ENVIRON(5)                                             ENVIRON(5)

          environ - user environment

          extern char **environ;

          An array of strings called the `environment' is made avail-
          able by exec(2) when a process begins.  By convention these
          strings have either the form `name=value', defining a vari-
          able, or `name(){value}', defining a function (see sh(1)).
          The following variables are used by various commands:

          PATH    The sequence of directory prefixes that sh, time,
                  nice(1), etc., apply in searching for a file known
                  by an incomplete path name.  The prefixes are sepa-
                  rated by `:'.  Login(1) sets PATH=:/bin:/usr/bin.

          HOME    A user's login directory, set by login(8) from the
                  password file passwd(5).

          TERM    The kind of terminal for which output is to be pre-
                  pared.  This information is used by commands, such
                  as nroff or plot(1), which may exploit special ter-
                  minal capabilities.  See /etc/termcap for a list of
                  terminal types.

          SHELL   The name of the login shell.

          The environment may be queried by getenv(3) or by the set or
          whatis commands of sh(1). Names may be placed in the envi-
          ronment by the export command by and `name=value' arguments
          in sh(1). Names may also be placed in the environment at the
          point of an exec(2). It is unwise to conflict with certain
          sh(1) variables that are frequently exported by `.profile'
          files: MAIL, PS1, PS2, IFS.

          sh(1), exec(2), getenv(3), term(7)