environ(5) UNIX System V 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 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) and strxfrm(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 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:
10/89 Page 1
environ(5) UNIX System V environ(5)
cat(1), ed(1), ls(1), and vi(1).
LCMESSAGES 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(1M) command. This
environment variable is used by exstr(1),
gettxt(1), gettxt(3C), and srchtxt(1).
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)].
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)].
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.
Page 2 10/89
environ(5) UNIX System V environ(5)
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 catopen(3C) uses 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. |
| %l The language element from LANG. |
| %t The territory element from LANG.|
| %c The codeset element from LANG. |
| %% 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.
PATH The sequence of directory prefixes that sh(1), time(1),
nice(1), nohup(1), and so forth, 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).)
SHELL When the shell is invoked, it scans the environment for this
name. If it is found and rsh is the filename part of its
value, the shell becomes a restricted shell. The value of
10/89 Page 3
environ(5) UNIX System V environ(5)
this variable should be specified with an absolute pathname.
The variable is used by make(1), ksh(1), sh(1), and vi(1),
among other commands.
TERM The kind of terminal for which output is to be prepared.
This information is used by commands, such as mm(1) or vi(1),
which may exploit special capabilities of that terminal.
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) and mktime(3C) to
override the default timezone. If the first character of TZ
is a colon (:), the behavior is implementation defined,
otherwise TZ has the form:
stdoffset[dst[offset],[start[/time],end[/time]]]
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 (-) or a plus (+) 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).
start/time,end/time
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.
Page 4 10/89
environ(5) UNIX System V environ(5)
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 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.
Implementation specific defaults are used for start and
end if these optional fields are not given.
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)).
SEE ALSO
chrtbl(1M), colltbl(1M), mkmsgs(1M), montbl(1M), netconfig(4),
strftime(4), passwd(4), profile(4) in the System Administrator's
Reference Manual
exec(2), addseverity(3C), catopen(3C), ctime(3C), ctype(3C), fmtmsg(3C),
getdate(3C), gettxt(3C), localeconv(3C), mbchar(3C), mktime(3C),
printf(3C), strcoll(3C), strftime(3C), strtod(3C), strxfrm(3C),
strftime(4), timezone(4)
cat(1), date(1), ed(1), fmtmsg(1), ls(1), login(1), nice(1), nohup(1),
sh(1), sort(1), time(1), vi(1) in the User's Reference Manual
getnetpath(3N), in the Programmer's Guide: Networking Interfaces
mm(1) in the DOCUMENTER'S WORKBENCH Software Technical Discussion and
Reference Manual
10/89 Page 5