environ(5) DG/UX 5.4.2 environ(5)
NAME
environ - user environment
DESCRIPTION
When a process begins execution, exec routines make 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.
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(4)).
LANG The string used to specify localization information that
allows users to work with different national conventions.
The setlocale(3C) function looks for the LANG environment
variable when it is called with "" as the locale
argument. LANG is used as the default locale if the
corresponding environment variable for a particular
category is unset.
For example, when setlocale() is invoked as
setlocale(LCCTYPE, ""),
setlocale() will query the LCCTYPE environment variable
first to see if it is set and non-null. If LCCTYPE 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 LCCTYPE are unset or null, the default
C locale will be used to set the LCCTYPE category.
Most commands will invoke
setlocale(LCALL, "")
prior to any other processing. This allows the command
to be used with different national conventions by setting
the appropriate environment variables.
The system-wide default value for LANG can be changed
with the sysadm(1M) command.
The following environment variables are supported to
correspond with each category of setlocale(3C):
LCCOLLATE This category specifies the collation
sequence being used. The information
corresponding to this category is stored
in a database created by the colltbl(1M)
command. This environment variable
affects strcoll(3C), strxfrm(3C) and the
regular expression code (see regexpr(3C)).
LCCTYPE This category specifies character
classification, character conversion, and
widths of multibyte characters. The
information corresponding to this category
is stored in a database created by the
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chrtbl(1M) command. The default C locale
corresponds to the 7-bit ASCII character
set. This environment variable is used by
ctype(3C), mbchar(3C), and many commands;
for example: cat(1), ed(1), ls(1), and
vi(1).
LCMESSAGES This category specifies the language of
the AT&T-style 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(1M) command. This
environment variable is used by exstr(1),
gettxt(1), gettxt(3C), and srchtxt(1).
The X/Open-style message facility does not
use this variable.
LCMONETARY 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 montbl(1M)
command. This environment variable is
used by localeconv(3C).
LCNUMERIC This category specifies the decimal and
thousands delimiters. The information
corresponding to this category is stored
in a database created by the chrtbl(1M)
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).
LCTIME This category specifies date and time
formats. The information corresponding to
this category is stored in a database
specified in strftime(4). 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)].
SEVLEVEL Define severity levels and associate and print strings
with them in standard format error messages [see
addseverity(3C), fmtmsg(1), and fmtmsg(3C)].
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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(3N) access the NETPATH environment variable.
NLSPATH Contains a sequence of templates which the X/Open-style
message facility uses when attempting to locate message
catalogs (see catopen(3C)). The AT&T-style message
facility does not use this variable. Each template
consists of an optional prefix, one or more substitution
fields, a filename and an optional suffix.
For example:
NLSPATH="/usr/lib/nls/msg/%N.cat"
defines that catopen() should look for all message
catalogs in the directory /usr/lib/nls/msg, 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. |
|%l The language element from LANG. |
|%t The territory element from LANG. |
|%c The codeset element from LANG. |
|%% A single % character. |
An empty +
s-
t-
r-
iπ-
g--
i-
s--
s-
u-
b-
s-
t-
i-
t-
u-
t-
e-
d--
i-
f--
tℏ-
e--
s-
p-
e-
c-
i-
f-
i-
e-
d-+
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:/usr/lib/nls/msg/%L/%N.cat"
indicates to catopen() that it should look for the
requested message catalog in name, name.cat and
/usr/lib/nls/msg/$LANG/name.cat.
The system-wide default value for NLSPATH can be changed
with the sysadm(1M) command.
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PATH The sequence of directory prefixes that sh(1), time(1),
nice(1), nohup(1), etc., 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).)
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.
CFTIME Historically, the default format string to be used by the
date(1) command and the ascftime() and cftime() routines
(see strftime(3C)). If CFTIME is not set or is null, the
default format string specified in the
/lib/cftime/LANGUAGE file (if it exists) is used in its
place (see cftime(4)). The use of CFTIME has generally
been subsumed by LANG and LCTIME.
CHRCLASS Historically, a value that corresponds to a file in
/lib/chrclass containing character classification and
conversion information. This information was used by
commands (such as cat(1), ed(1), and sort(1)) to classify
characters as alphabetic, printable, upper case, and so
on, and to convert characters to upper or lower case.
The use of CHRCLASS has generally been subsumed by LANGF1
and LCCTYPE. For more detail, see ctype(3C).
LANGUAGE Historically, a language for which a printable file by
that name exists in /lib/cftime. This information was
used by commands (such as date(1), ls(1), and sort(1)) to
print date and time information in the language
specified. The use of LANGUAGE has generally been
subsumed by LANG and LCTIME.
TZ Time zone information. The contents of the environment
variable named TZ are used by the functions ctime(3C),
localtime() (see ctime(3C)), strftime(3C) ascftime() (see
strftime(3C)), cftime() (see strftime(3C)), and
mktime(3C) to override the default timezone. The value
of TZ has one of the two forms (spaces inserted for
clarity):
:characters
or:
std offset dst offset, rule
If TZ is of the first format (i.e., if the first
character is a colon), the string following the colon is
the name of the timezone that will be loaded in from the
/usr/lib/locale/TZ directory. For example, if TZ was set
to :US/Eastern, it would load the
/usr/lib/local/TZ/US/Eastern timezone definition file.
The timezones under this directory are produced with the
zic(1) command.
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The expanded format (for all TZs whose value does not
have a colon as the first character) is as follows:
stdoffset[dst[offset],[start[/time],end[/time]]]
Where:
std and dst
Three or more bytes that are the designation for
the standard (std) and daylight savings time (dst)
timezones. Only std is required, if dst is
missing, then daylight savings time does not apply
in this locale. Upper- and lower-case letters are
allowed. Any characters except a leading colon
(:), digits, a comma (,), a minus (-), a plus (+),
or an ASCII NUL are allowed.
offset Indicates 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 may 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 may 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 between 0 and 59. Out of
range values may cause unpredictable behavior. If
preceded by a ``-'', the timezone is east of the
Prime Meridian; otherwise it is west (which may be
indicated by an optional preceding ``+'' sign).
rule Indicates when to change to and back from summer
time. The rule has the form:
start/time,end/time
Which indicates 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 happens. 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
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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 dth 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 dth day occurs.
Day zero is Sunday.
The time has the same format as offset except that
no leading sign (``-'' or ``+'') is allowed. The
default, if time is not given is 02:00:00.
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 (see profile(4)).
Whenever ascftime(), cftime(), ctime(), localtime(), mktime(), or
strftime() is called, the time zone names contained in the external
variable tzname() shall be set as if the tzset() function had been
called.
Applications are explicitly allowed to change TZ and have the changed
TZ apply to themselves.
The system-wide default value for TZ can be changed with the
sysadm(1M) command.
NOTE: There is an unfortunate potential for confusion with time
zones identified by an offset from GMT. The TZ value GMT+5,
according to the rules presented here, is equivalent to EST5
-- 5 hours West of GTM. There is also a timezone definition
file that can be used by setting TZ to :GMT+5, but this file
defines the time zone 5 hours East of GMT. Existing practice
requires that both these notations be supported.
SEE ALSO
chrtbl(1M), colltbl(1M), montbl(1M), netconfig(4), strftime(4),
passwd(4), profile(4).
exec(2), addseverity(3C), catopen(3C), ctime(3C), ctype(3C),
fmtmsg(3C), getdate(3C), getenv(3C), gettxt(3C), localeconv(3C),
mbchar(3C), mktime(3C), printf(3C), strcoll(3C), strftime(3C),
strtod(3C), strxfrm(3C), strftime(4), time(4), timezone(4).
cat(1), date(1), ed(1), gencat(1), fmtmsg(1), ls(1), login(1),
mkmsgs(1), nice(1), nohup(1), sh(1), sort(1), time(1), vi(1), zic(1).
getnetpath(3N), in the Programmer's Guide: Networking Interfaces.
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COPYRIGHTS
Portions of this text are reprinted from IEEE Std 1003.1-1988,
Portable Operating System Interface for Computer Environment,
copyright © 1988 by the Institute of Electrical and Electronics
Engineers, Inc., with the permission of the IEEE Standards
Department. To purchase IEEE Standards, call 800/678-IEEE.
In the event of a discrepancy between the electronic and the original
printed version, the original version takes precedence.
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