ENVIRON(5) File Formats Manual ENVIRON(5)
environ - user environment
extern char **environ;
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
HOME A user's login directory, set by login(1) from the password file
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.
exec(2), sh(1), term(7), login(1)