NAME

environ − user environment

USAGE

extern char **environ;

DESCRIPTION

An array of strings called the ‘environment’ is made available by execve(2) when a process begins.  By convention these strings have the form ‘name=value’.

Certain environment variables are predefined by the system at login time.  We refer to these variables  as  [predefined]  below.  Some of these predefined variables cannot be deleted or changed by /com/sh or any callers of ev_$....  Such  variables are referred to as [privileged] in the following list. 

The following names are used by various commands:

PATH The sequence of directory prefixes that sh, time, nice(1), etc., apply in searching for a file known by an incomplete pathname.  The prefixes are separated by ‘:’.  Login(1) sets PATH=:/usr/ucb:/bin:/usr/bin. 

HOME A user’s log-in directory, set by login(1) from the password file passwd(5). 

TERM [Predefined] The kind of terminal for which output is to be prepared.  This information is used by commands, such as nroff or plot(1G), which may exploit special terminal capabilities.  See /etc/termcap (termcap(5)) for a list of terminal types.

SHELL The filename of the user’s log-in shell. 

TERMCAP
The string describing the terminal in TERM, or the name of the termcap file, see termcap(5),termcap(3X). 

EXINIT A startup list of commands read by ex(1), edit(1), and vi(1). 

USER [Predefined, Privileged] The log-in name of the user. 

NODETYPE
[Predefined, Privileged] Model number of the node, e.g., dn300.

PROJECT [Predefined, Privileged] Project associated with log-in name. 

ORGANIZATION
[Predefined, Privileged] Organization associated with log-in name.

NODEID [Predefined, Privileged] Hexadecimal ID of node, e.g., 2b1f. 

NAMECHARS
(Applies only to SR9 name mapping) Interpret certain characters as ‘special’, e.g., retain special meaning for ‘~’.

SYSTYPE Version of DOMAIN/IX currently set as ‘systype’. 

UNIXNAMES
Select character mapping for either SR8 or SR9 style.

SBRKSIZE If set (to a decimal integer), it is equivalent, in a running program, to having made a call to the function set_sbrk_size.  If no argument is specified, the 256k limit applies.  The maximum value that can be assigned is machine dependent. 

INPROCESS
If set, run new programs in the Shell process (unless part of a pipe or running in background). Otherwise, always spawn a new process to run a new program. (This variable is unset by default, unless it has been set in the DOMAIN DM, by putting a line of the form “env INPROCESS ‘true‘ in the file ‘node_data/startup.type.) 

Further names may be placed in the environment by the export command and ‘name=value’ arguments in sh(1), or by the setenv command if you use csh(1).  Arguments may also be placed in the environment at the point of an execve(2).  It is unwise to conflict with certain sh(1) variables that are frequently exported by ‘.profile’ files: MAIL, PS1, PS2, IFS. 

RELATED INFORMATION

csh(1), ex(1),Theenvironmentvariableis login(1), sh(1), execve(2), system(3), termcap(3X), termcap(5)