projects / unix-history / blame
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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) |