NAME

environ − user environment

DESCRIPTION

An array of strings called the “environment” is made available by exec(2) when a process begins. By convention, these strings have the form “name=value”. The following names are used by various commands:

CFTIME The default format string to be used by the date(1) command and the ascftime() and cftime() routines [see ctime(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)].

CHRCLASS A value that corresponds to a file in /lib/chrclass containing character classification and conversion information.  This information is used by commands (such as cat(1), ed(1), sort(1), vi(1), etc.) to classify characters as alphabetic, printable, uppercase, etc., and to convert characters to uppercase or lowercase.

When a program or command begins execution, the tables containing this information are initialized based on the value of CHRCLASS.  If CHRCLASS is nonexistent, null, set to a value for which no file exists in /lib/chrclass, or errors occur while reading the file, the ASCII character set is used.  During execution, a program or command can change the values in these tables by calling the setchrclass() routine.  For more detail, see ctype(3C).

These tables are created using the chrtbl(1M) command.

HOME The name of the user’s login directory, set by login(1) from the password file [see passwd(4)].

LANGUAGE A language for which a printable file by that name exists in /lib/cftime.  This information is used by commands (such as date(1), ls(1), sort(1), etc.) to print date and time information in the language specified.

If LANGUAGE is nonexistent, null, set to a value for which no file exists in /lib/cftime, or errors occur while reading the file, the last language requested will be used.  (If no language has been requested, the language usa_english is assumed.)  For a description of the content of files in /lib/cftime, see cftime(4).

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=:/bin:/usr/bin.  (For more detail, see the "Execution" section of the sh(1) manual page.)

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 simplest format is xxxnzzz where xxx is the standard local time zone abbreviation, n is the difference in hours from GMT (Greenwich Mean Time), and zzz is the abbreviation for an alternate time zone (usually the daylight-saving local time zone), if any; for example,

TZ="EST5EDT"

The most complex format allows you to specify the difference in hours of the alternate time zone from GMT and the starting day and time and ending day and time for using this alternate time zone.  For example, in 1985 the complex format corresponding to the above simple example is:

TZ="EST5:00:00EDT4:00:00;118/2:00:00,300/2:00:00"

When the above complex format is used, it must be surrounded by double quotes.  For more details, see ctime(3C) and timezone(4).

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

cat(1), chrtbl(1M), date(1), ed(1), env(1), ls(1), login(1), nice(1), nohup(1), sh(1), sort(1), time(1), vi(1), exec(2), ctime(3C), ctype(3C), cftime(4), passwd(4), profile(4), timezone(4). 

NOTES

Administrators should note the following: if you attempt to set the current date to one of the dates that the standard and alternate time zones change (for example, the date that daylight time is starting or ending), and you attempt to set the time to a time in the interval between the end of standard time and the beginning of the alternate time (or the end of the alternate time and the beginning of standard time), the results are unpredictable. 

ADDED VALUE

This entry, supplied by SunSoft, Inc., contains enhancements to UNIX ­System V. 

\*U  —  Version 1.0