v7 man page for environ

ENVIRON(5)							File Formats Manual							ENVIRON(5)

NAME
       environ - user environment

SYNOPSIS
       extern char **environ;

DESCRIPTION
       An array of strings called the `environment' is made available by exec(2) when a process begins.  By convention these strings have the form
       `name=value'.  The following names 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 separated by `:'.  Login(1) sets PATH=:/bin:/usr/bin.

       HOME   A user's login directory, set by login(1) from the password file passwd(5).

       TERM   The  kind of terminal for which output is to be prepared.  This information is used by commands, such as nroff or plot(1), which may
	      exploit special terminal capabilities.  See term(7) for a list of terminal types.

       Further names may be placed in the environment by the export command and `name=value' arguments in sh(1), or by exec(2).  It is	unwise	to
       conflict with certain Shell variables that are frequently exported by `.profile' files: MAIL, PS1, PS2, IFS.

SEE ALSO
       exec(2), sh(1), term(7), login(1)

																	ENVIRON(5)