ENVIRON(7) Device and Network Interfaces ENVIRON(7)


environ - user environment


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.


The name of the user's login directory, set by login(1) from the
password file; see passwd(5).


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


If set to a valid, non-empty string value, override the values of
LANG and all the other LC_*variables.


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).


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).


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).


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).


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).


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).


Controls which standard format message components fmtmsg selects when
messages are displayed to stderr; see fmtmsg(1) and fmtmsg(3C).


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


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:


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:


The value of the name parameter passed to catopen().


The value of LANG or LC_MESSAGES.


The language element from LANG or LC_MESSAGES.


The territory element from LANG or LC_MESSAGES.


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:


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


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).


Define severity levels and associate and print strings with them in
standard format error messages; see addseverity(3C), fmtmsg(1), and


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.


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):



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


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.


Indicate the value one must add to the local time to arrive at
Coordinated Universal Time. The offset has the form:


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).


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:


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


The zero-based Julian day (0 <= n <= 365). Leap days are
counted, and it is possible to refer to February 29.


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.


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)