[unix-history] / usr / man / man5 / environ.5

.TH ENVIRON 5
.SH NAME
environ \- user environment
.SH SYNOPSIS
.B extern char **environ;
.SH DESCRIPTION
An array of strings called the `environment' is
made available by
.IR exec (2)
when a process begins.
By convention these strings have the form
`name=value'.
The following names are used by various commands:
.TP
PATH
The sequence of directory prefixes that
.I sh, time,
.IR nice (1),
etc.,
apply in searching for a file known by an incomplete path name.
The prefixes are separated by `:'.
.IR Login (1)
sets PATH=:/bin:/usr/bin.
.TP
HOME
A user's login directory, set by
.IR login (1)
from the password file
.IR passwd (5).
.TP
TERM
The kind of terminal for which output is to be prepared.
This information is used by commands, such as
.I nroff
or
.IR plot (1),
which may exploit special terminal capabilities.
See
.IR term (7)
for a list of terminal types.
.PP
Further names may be placed in the environment by
the
.I export
command and `name=value' arguments in
.IR sh (1),
or by 
.IR exec (2).
It is unwise to conflict with
certain Shell variables that are frequently exported by
`.profile' files:
MAIL, PS1, PS2, IFS.
.SH SEE ALSO
exec(2), sh(1), term(7), login(1)
Commit	Line	Data
72972dd0 TL	1	.TH ENVIRON 5
	2	.SH NAME
	3	environ \- user environment
	4	.SH SYNOPSIS
	5	.B extern char **environ;
	6	.SH DESCRIPTION
	7	An array of strings called the `environment' is
	8	made available by
	9	.IR exec (2)
	10	when a process begins.
	11	By convention these strings have the form
	12	`name=value'.
	13	The following names are used by various commands:
	14	.TP
	15	PATH
	16	The sequence of directory prefixes that
	17	.I sh, time,
	18	.IR nice (1),
	19	etc.,
	20	apply in searching for a file known by an incomplete path name.
	21	The prefixes are separated by `:'.
	22	.IR Login (1)
	23	sets PATH=:/bin:/usr/bin.
	24	.TP
	25	HOME
	26	A user's login directory, set by
	27	.IR login (1)
	28	from the password file
	29	.IR passwd (5).
	30	.TP
	31	TERM
	32	The kind of terminal for which output is to be prepared.
	33	This information is used by commands, such as
	34	.I nroff
	35	or
	36	.IR plot (1),
	37	which may exploit special terminal capabilities.
	38	See
	39	.IR term (7)
	40	for a list of terminal types.
	41	.PP
	42	Further names may be placed in the environment by
	43	the
	44	.I export
	45	command and `name=value' arguments in
	46	.IR sh (1),
	47	or by
	48	.IR exec (2).
	49	It is unwise to conflict with
	50	certain Shell variables that are frequently exported by
	51	`.profile' files:
	52	MAIL, PS1, PS2, IFS.
	53	.SH SEE ALSO
	54	exec(2), sh(1), term(7), login(1)