ENVIRON(7) Standards, Environments, and Macros ENVIRON(7)
NAME
environ - user environment
DESCRIPTION
When a process begins execution, one of the
exec family of functions
makes available an array of strings called the environment; see
exec(2).
By convention, these strings have the form
variable=value, for example,
PATH=/sbin:/usr/sbin. These environmental variables provide a way to make
information about a program's environment available to programs.
A name may be placed in the environment by the
export command and
name=
value arguments in
sh(1), or by one of the
exec functions. It is
unwise to conflict with certain shell variables such as
MAIL,
PS1,
PS2,
and
IFS that are frequently exported by
.profile files; see
profile(5).
The following environmental variables can be used by applications and are
expected to be set in the target run-time environment.
HOME The name of the user's login directory, set by
login(1) from the
password file; see
passwd(5).
LANG The string used to specify internationalization information that
allows users to work with different national conventions. The
setlocale(3C) and
newlocale(3C) functions check the
LANG environment
variable when they are called with
"" as the
locale argument.
LANG is used as the default locale if the corresponding environment
variable for a particular category is unset or null. If, however,
LC_ALL is set to a valid, non-empty value, its contents are used to
override both the
LANG and the other
LC_* variables. For example,
when invoked as
setlocale(LC_CTYPE, ""),
setlocale() will query the
LC_CTYPE environment variable first to see if it is set and non-null.
If
LC_CTYPE is not set or null, then
setlocale() will check the
LANG environment variable to see if it is set and non-null. If both
LANG and
LC_CTYPE are unset or
NULL, the default "C" locale will be used
to set the
LC_CTYPE category.
Most commands will invoke
setlocale(LC_ALL, "") prior to any other
processing. This allows the command to be used with different
national conventions by setting the appropriate environment
variables. In addition, some commands will use
uselocale(3C) to set a
thread-specific locale.
The following environment variables correspond to each category of
setlocale(3C):
LC_ALL If set to a valid, non-empty string value, override the values of
LANG and all the other
LC_*variables.
LC_COLLATE This category specifies the character collation sequence being
used. The information corresponding to this category is stored
in a database created by the
localedef(1) command. This
environment variable affects
strcoll(3C) and
strxfrm(3C).
LC_CTYPE This category specifies character classification, character
conversion, and widths of multibyte characters. When
LC_CTYPE is
set to a valid value, the calling utility can display and handle
text and file names containing valid characters for that locale;
Extended Unix Code (EUC) characters where any individual
character can be 1, 2, or 3 bytes wide; and EUC characters of 1,
2, or 3 column widths. The default "C" locale corresponds to the
7-bit
ASCII character set; only characters from ISO 8859-1 are
valid. The information corresponding to this category is stored
in a database created by the
localedef() command. This
environment variable is used by
ctype(3C),
mblen(3C), and many
commands, such as
cat(1),
ed(1),
ls(1), and
vi(1).
LC_MESSAGES This category specifies the language of the message database
being used. For example, an application may have one message
database with French messages, and another database with German
messages. Message databases are created by the
mkmsgs(1) command.
This environment variable is used by
exstr(1),
gettxt(1),
srchtxt(1),
gettxt(3C), and
gettext(3C).
LC_MONETARY This category specifies the monetary symbols and delimiters used
for a particular locale. The information corresponding to this
category is stored in a database created by the
localedef(1) command. This environment variable is used by
localeconv(3C).
LC_NUMERIC This category specifies the decimal and thousands delimiters. The
information corresponding to this category is stored in a
database created by the
localedef() command. The default
C locale corresponds to
"." as the decimal delimiter and no
thousands delimiter. This environment variable is used by
localeconv(3C),
printf(3C), and
strtod(3C).
LC_TIME This category specifies date and time formats. The information
corresponding to this category is stored in a database specified
in
localedef(). The default
C locale corresponds to U.S. date and
time formats. This environment variable is used by many commands
and functions; for example:
at(1),
calendar(1),
date(1),
strftime(3C), and
getdate(3C).
MSGVERB Controls which standard format message components
fmtmsg selects when
messages are displayed to
stderr; see
fmtmsg(1) and
fmtmsg(3C).
NETPATH A colon-separated list of network identifiers. A network identifier
is a character string used by the Network Selection component of the
system to provide application-specific default network search paths.
A network identifier must consist of non-null characters and must
have a length of at least 1. No maximum length is specified. Network
identifiers are normally chosen by the system administrator. A
network identifier is also the first field in any
/etc/netconfig file
entry.
NETPATH thus provides a link into the
/etc/netconfig file and
the information about a network contained in that network's entry.
/etc/netconfig is maintained by the system administrator. The library
routines described in
getnetpath(3NSL) access the
NETPATH environment
variable.
NLSPATH Contains a sequence of templates which
catopen(3C) and
gettext(3C) use when attempting to locate message catalogs. Each template
consists of an optional prefix, one or more substitution fields, a
filename and an optional suffix. For example:
NLSPATH="/system/nlslib/%N.cat"
defines that
catopen() should look for all message catalogs in the
directory
/system/nlslib, where the catalog name should be
constructed from the
name parameter passed to
catopen(),
%N, with the
suffix
.cat.
Substitution fields consist of a
% symbol, followed by a single-
letter keyword. The following keywords are currently defined:
%N The value of the
name parameter passed to
catopen().
%L The value of
LANG or
LC_MESSAGES.
%l The language element from
LANG or
LC_MESSAGES.
%t The territory element from
LANG or
LC_MESSAGES.
%c The codeset element from
LANG or
LC_MESSAGES.
%% A single
% character.
An empty string is substituted if the specified value is not
currently defined. The separators "
_" and "
." are not included in
%t and
%c substitutions.
Templates defined in
NLSPATH are separated by colons (
:). A leading
colon or two adjacent colons (
::) is equivalent to specifying
%N.
For example:
NLSPATH=":%N.cat:/nlslib/%L/%N.cat"
indicates to
catopen() that it should look for the requested message
catalog in
name,
name.cat and
/nlslib/$LANG/name.cat. For
gettext(),
%N automatically maps to "messages".
If
NLSPATH is unset or
NULL,
catopen() and
gettext() call
setlocale(3C), which checks
LANG and the
LC_* variables to locate
the message catalogs.
NLSPATH will normally be set up on a system wide basis (in
/etc/profile) and thus makes the location and naming conventions
associated with message catalogs transparent to both programs and
users.
PATH The sequence of directory prefixes that
sh(1),
time(1),
nice(1),
nohup(1), and other utilities apply in searching for a file known by
an incomplete path name. The prefixes are separated by colons (
:).
login(1) sets
PATH=/usr/bin. For more detail, see
sh(1).
SEV_LEVEL Define severity levels and associate and print strings with them in
standard format error messages; see
addseverity(3C),
fmtmsg(1), and
fmtmsg(3C).
TERM The kind of terminal for which output is to be prepared. This
information is used by commands, such as
vi(1), which may exploit
special capabilities of that terminal.
TZ Timezone information. The contents of this environment variable are
used by the functions
ctime(3C),
localtime(3C),
strftime(3C), and
mktime(3C) to override the default timezone. The value of
TZ has one
of the two formats (spaces inserted for clarity):
:characters
or
std offset dst offset, rule
If
TZ is of the first format (that is, if the first character is a
colon (:)), or if
TZ is not of the second format, then
TZ designates
a path to a timezone database file relative to
/usr/share/lib/zoneinfo/, ignoring a leading colon if one exists.
Otherwise,
TZ is of the second form, which when expanded is as
follows:
stdoffset[
dst[
offset][,
start[/
time],
end[/
time]]]
std and
dst Indicate no less than three, nor more than {
TZNAME_MAX}, bytes
that are the designation for the standard (
std) or the
alternative (
dst, such as Daylight Savings Time) timezone. Only
std is required; if
dst is missing, then the alternative time
does not apply in this timezone. Each of these fields can occur
in either of two formats, quoted or unquoted:
o In the quoted form, the first character is the less-
than ('<') character and the last character is the
greater-than ('>') character. All characters between
these quoting characters are alphanumeric characters
from the portable character set in the current locale,
the plus-sign ('+') character, or the minus-sign ('-')
character. The
std and
dst fields in this case do not
include the quoting characters.
o In the unquoted form, all characters in these fields
are alphabetic characters from the portable character
set in the current locale.
The interpretation of these fields is unspecified if either field
is less than three bytes (except for the case when
dst is
missing), more than {
TZNAME_MAX} bytes, or if they contain
characters other than those specified.
offset Indicate the value one must add to the local time to arrive at
Coordinated Universal Time. The offset has the form:
hh[:
mm[:
ss]]
The minutes (
mm) and seconds (
ss) are optional. The hour (
hh) is
required and can be a single digit. The
offset following
std is
required. If no
offset follows
dst, daylight savings time is
assumed to be one hour ahead of standard time. One or more digits
can be used. The value is always interpreted as a decimal
number. The hour must be between 0 and 24, and the minutes (and
seconds), if present, must be between 0 and 59. Out of range
values can cause unpredictable behavior. If preceded by a "-",
the timezone is east of the Prime Meridian. Otherwise, it is west
of the Prime Meridian (which can be indicated by an optional
preceding "
+" sign).
start/
time,
end/
time Indicate when to change to and back from daylight savings time,
where
start/time describes when the change from standard time to
daylight savings time occurs, and
end/time describes when the
change back occurs. Each
time field describes when, in current
local time, the change is made.
The formats of
start and
end are one of the following:
Jn The Julian day
n (1 <=
n <= 365). Leap days are not counted.
That is, in all years, February 28 is day 59 and March 1 is
day 60. It is impossible to refer to the occasional February
29.
n The zero-based Julian day (0 <=
n <= 365). Leap days are
counted, and it is possible to refer to February 29.
Mm.n.d The
d^th day, (0 <=
d <= 6) of week
n of month
m of the year
(1 <=
n <= 5, 1 <=
m <= 12), where week 5 means "the last
d-day in month
m" which may occur in either the fourth or the
fifth week). Week 1 is the first week in which the
d^th day
occurs. Day zero is Sunday.
Implementation specific defaults are used for
start and
end if
these optional fields are not specified.
The
time has the same format as
offset except that no leading
sign ("-" or "+" ) is allowed. If
time is not specified, the
default value is 02:00:00.
SEE ALSO
cat(1),
date(1),
ed(1),
fmtmsg(1),
localedef(1),
login(1),
ls(1),
mkmsgs(1),
nice(1),
nohup(1),
sh(1),
sort(1),
time(1),
vi(1),
exec(2),
addseverity(3C),
catopen(3C),
ctime(3C),
ctype(3C),
fmtmsg(3C),
getdate(3C),
gettext(3C),
gettxt(3C),
localeconv(3C),
mblen(3C),
mktime(3C),
newlocale(3C),
printf(3C),
setlocale(3C),
strcoll(3C),
strftime(3C),
strtod(3C),
strxfrm(3C),
uselocale(3C),
getnetpath(3NSL),
TIMEZONE(5),
netconfig(5),
passwd(5),
profile(5) June 26, 2014
ENVIRON(7)