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1 | .\" Copyright (c) 1980 Regents of the University of California. |
2 | .\" All rights reserved. The Berkeley software License Agreement | |
3 | .\" specifies the terms and conditions for redistribution. | |
4 | .\" | |
5 | .\" @(#)environ.5 4.1 (Berkeley) %G% | |
6 | .\" | |
7 | .TH ENVIRON 5 | |
8 | .UC 4 | |
9 | .SH NAME | |
10 | environ \- user environment | |
11 | .SH SYNOPSIS | |
12 | .B extern char **environ; | |
13 | .SH DESCRIPTION | |
14 | An array of strings called the `environment' is | |
15 | made available by | |
16 | .IR exec (2) | |
17 | when a process begins. | |
18 | By convention these strings have the form | |
19 | .RI ` name = value '. | |
20 | The following names are used by various commands: | |
21 | .TP "\w'TERMCAP 'u" | |
22 | PATH | |
23 | The sequence of directory prefixes that | |
24 | .I sh, time, | |
25 | .IR nice (1), | |
26 | etc., | |
27 | apply in searching for a file known by an incomplete path name. | |
28 | The prefixes are separated by `:'. | |
29 | .IR Login (1) | |
30 | sets PATH=:/usr/ucb:/bin:/usr/bin. | |
31 | .TP | |
32 | HOME | |
33 | A user's login directory, set by | |
34 | .IR login (1) | |
35 | from the password file | |
36 | .IR passwd (5). | |
37 | .TP | |
38 | TERM | |
39 | The kind of terminal for which output is to be prepared. | |
40 | This information is used by commands, such as | |
41 | .I nroff | |
42 | or | |
43 | .IR plot (1), | |
44 | which may exploit special terminal capabilities. | |
45 | See | |
46 | .I /etc/termcap | |
47 | .RI ( termcap (5)) | |
48 | for a list of terminal types. | |
49 | .TP | |
50 | SHELL | |
51 | The file name of the users login shell. | |
52 | .TP | |
53 | TERMCAP | |
54 | The string describing the terminal in TERM, | |
55 | or the name of the termcap file, see | |
56 | .IR termcap (5), termlib (3). | |
57 | .TP | |
58 | EXINIT | |
59 | A startup list of commands read by | |
60 | .IR ex (1), | |
61 | .IR edit (1), | |
62 | and | |
63 | .IR vi (1). | |
64 | .TP | |
65 | USER | |
66 | The login name of the user. | |
67 | .PP | |
68 | Further names may be placed in the environment by | |
69 | the | |
70 | .I export | |
71 | command and `name=value' arguments in | |
72 | .IR sh (1), | |
73 | or by the | |
74 | .I setenv | |
75 | command if you use | |
76 | .IR csh (1). | |
77 | Arguments may also be placed in the environment at the point of an | |
78 | .IR exec (2). | |
79 | It is unwise to conflict with | |
80 | certain | |
81 | .IR sh (1) | |
82 | variables that are frequently exported by | |
83 | `.profile' files: | |
84 | MAIL, PS1, PS2, IFS. | |
85 | .SH SEE ALSO | |
86 | csh(1), ex(1), login(1), sh(1), exec(2), system(3), termlib(3), termcap(5), term(7) |