Tribblix: manual page: environ.7

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.

NAME

DESCRIPTION

SEE ALSO