6d34415f67
- Add a better introduction to the DESCRIPTION section - Add a description for MANPATH and POSIXLY_CORRECT - Asorted improvements for the usage of some macros PR: 43823 Submitted by: Lyndon Nerenberg <lyndon at orthanc dot ab dot ca> Reviewed by: 0mp, bcr Approved by: 0mp, bcr MFC after: 1 week Differential Revision: https://reviews.freebsd.org/D25912
315 lines
7.8 KiB
Groff
315 lines
7.8 KiB
Groff
.\" Copyright (c) 1983, 1990, 1993
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.\" The Regents of the University of California. All rights reserved.
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.\"
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.\" Redistribution and use in source and binary forms, with or without
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.\" modification, are permitted provided that the following conditions
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.\" are met:
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.\" 1. Redistributions of source code must retain the above copyright
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.\" notice, this list of conditions and the following disclaimer.
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.\" 2. Redistributions in binary form must reproduce the above copyright
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.\" notice, this list of conditions and the following disclaimer in the
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.\" documentation and/or other materials provided with the distribution.
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.\" 3. Neither the name of the University nor the names of its contributors
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.\" may be used to endorse or promote products derived from this software
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.\" without specific prior written permission.
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.\"
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.\" THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
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.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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.\" ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
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.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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.\" SUCH DAMAGE.
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.\"
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.\" @(#)environ.7 8.3 (Berkeley) 4/19/94
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.\" $FreeBSD$
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.\"
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.Dd August 5, 2020
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.Dt ENVIRON 7
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.Os
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.Sh NAME
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.Nm environ
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.Nd user environment
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.Sh SYNOPSIS
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.Ar extern char **environ ;
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.Sh DESCRIPTION
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An array of strings, called the
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.Ar environment
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is made available to each process by
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.Xr execve 2
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when a process begins.
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By convention these strings have the form
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.Va name Ns No = Ns Ar value ,
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and are referred to as
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.Dq environment variables .
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A process can query, update, and delete these strings using the
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.Xr getenv 3 ,
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.Xr setenv 3 ,
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and
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.Xr unsetenv 3
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functions, respectively.
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The shells also provide commands to manipulate the environment;
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they are described in the respective shell manual pages.
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.Pp
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What follows is a list of environment variables typically
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seen on a
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.Ux
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system.
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It includes only those variables that a user can expect to see during their
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day-to-day use of the system, and is far from complete.
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Environment variables specific to a particular program or library function
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are documented in the
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.Sx ENVIRONMENT
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section of the appropriate manual page.
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.Sh ENVIRONMENT
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.Bl -tag -width LD_LIBRARY_PATH
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.It Ev BLOCKSIZE
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The size of the block units used by several disk-related commands,
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most notably
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.Xr df 1 ,
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.Xr du 1
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and
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.Xr ls 1 .
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.Ev BLOCKSIZE
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may be specified in units of a byte by specifying a number,
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in units of a kilobyte by specifying a number followed by
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.Ql K
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or
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.Ql k ,
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in units of a megabyte by specifying a number followed by
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.Ql M
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or
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.Ql m ,
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and in units of a gigabyte by specifying a number followed
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by
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.Ql G
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or
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.Ql g .
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Sizes less than 512 bytes or greater than a gigabyte are ignored.
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This variable is processed by the
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.Xr getbsize 3
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function.
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.It Ev COLUMNS
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The user's preferred width in column positions for the terminal.
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Utilities such as
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.Xr ls 1
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and
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.Xr who 1
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use this to format output into columns.
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If unset or empty, utilities will use an
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.Xr ioctl 2
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call to ask the terminal driver for the width.
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.It Ev EDITOR
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Default editor name.
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.It Ev EXINIT
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A startup list of commands read by
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.Xr ex 1
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and
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.Xr vi 1 .
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.It Ev HOME
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A user's login directory, set by
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.Xr login 1
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from the password file
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.Xr passwd 5 .
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.It Ev LANG
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This variable configures all programs which use
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.Xr setlocale 3
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to use the specified locale unless the
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.Ev LC_*
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variables are set.
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.It Ev LC_ALL
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Overrides the values of
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.Ev LC_COLLATE ,
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.Ev LC_CTYPE ,
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.Ev LC_MESSAGES ,
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.Ev LC_MONETARY ,
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.Ev LC_NUMERIC ,
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.Ev LC_TIME
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and
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.Ev LANG .
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.It Ev LC_COLLATE
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Locale to be used for ordering of strings.
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.It Ev LC_CTYPE
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Locale to be used for character classification
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(letter, space, digit, etc.) and for interpreting byte sequences as
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multibyte characters.
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.It Ev LC_MESSAGES
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Locale to be used for diagnostic messages.
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.It Ev LC_MONETARY
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Locale to be used for interpreting monetary input
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and formatting output.
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.It Ev LC_NUMERIC
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Locale to be used for interpreting numeric input and
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formatting output.
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.It Ev LC_TIME
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Locale to be used for interpreting dates input and
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for formatting output.
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.It Ev MAIL
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The location of the user's
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mailbox instead of the default in /var/mail,
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used by
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.Xr mail 1 ,
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.Xr sh 1 ,
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and many other mail clients.
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.It Ev MANPATH
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The sequence of directories, separated by colons, searched by
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.Xr man 1
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when looking for manual pages.
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.It Ev NLSPATH
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List of directories to be searched for the message catalog referred to by
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.Ev LC_MESSAGES .
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See
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.Xr catopen 3 .
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.It Ev PAGER
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Default paginator program.
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The program specified by this variable is used by
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.Xr mail 1 ,
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.Xr man 1 ,
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.Xr ftp 1 ,
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etc, to display information which is longer than the current display.
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.It Ev PATH
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The sequence of directories, separated by colons, searched by
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.Xr csh 1 ,
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.Xr sh 1 ,
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.Xr system 3 ,
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.Xr execvp 3 ,
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etc, when looking for an executable file.
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.Ev PATH
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is set to ``/usr/bin:/bin'' initially by
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.Xr login 1 .
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.It Ev POSIXLY_CORRECT
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When set to any value, this environment variable modifies the behaviour
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of certain commands to (mostly) execute in a strictly POSIX-compliant manner.
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.It Ev PRINTER
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The name of the default printer to be used by
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.Xr lpr 1 ,
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.Xr lpq 1 ,
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and
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.Xr lprm 1 .
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.It Ev PWD
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The current directory pathname.
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.It Ev SHELL
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The full pathname of the user's login shell.
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.It Ev TERM
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The kind of terminal for which output is to be prepared.
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This information is used by commands, such as
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.Xr nroff 1
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or
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.Xr plot 1
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which may exploit special terminal capabilities.
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See
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.Pa /usr/share/misc/termcap
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.Pq Xr termcap 5
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for a list of terminal types.
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.It Ev TERMCAP
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The string describing the terminal in
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.Ev TERM ,
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or, if
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it begins with a '/', the name of the termcap file.
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See
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.Ev TERMPATH
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below, and
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.Xr termcap 5 .
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.It Ev TERMPATH
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A sequence of pathnames of termcap files, separated by colons or spaces,
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which are searched for terminal descriptions in the order listed.
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Having
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no
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.Ev TERMPATH
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is equivalent to a
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.Ev TERMPATH
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of
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.Pa $HOME/.termcap:/etc/termcap .
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.Ev TERMPATH
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is ignored if
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.Ev TERMCAP
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contains a full pathname.
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.It Ev TMPDIR
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The directory in which to store temporary files.
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Most applications use either
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.Pa /tmp
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or
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.Pa /var/tmp .
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Setting this variable will make them use another directory.
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.It Ev TZ
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The timezone to use when displaying dates.
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The normal format is a pathname relative to
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.Pa /usr/share/zoneinfo .
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For example, the command
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.Pp
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.Dl env TZ=America/Los_Angeles date
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.Pp
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displays the current time in California.
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See
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.Xr tzset 3
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for more information.
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.It Ev USER
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The login name of the user.
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It is recommended that portable applications use
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.Ev LOGNAME
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instead.
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.El
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.Pp
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Further names may be placed in the environment by the
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.Ic export
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command and
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.Ar name=value
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arguments in
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.Xr sh 1 ,
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or by the
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.Ic setenv
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command if you use
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.Xr csh 1 .
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It is unwise to change certain
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.Xr sh 1
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variables that are frequently exported by
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.Pa .profile
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files, such as
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.Ev MAIL ,
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.Ev PS1 ,
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.Ev PS2 ,
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and
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.Ev IFS ,
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unless you know what you are doing.
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.Pp
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The current environment variables can be printed with
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.Xr env 1 ,
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.Xr set 1
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or
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.Xr printenv 1
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in
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.Xr sh 1
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and
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.Xr env 1 ,
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.Xr printenv 1
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or the
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.Cm printenv
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built-in command in
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.Xr csh 1 .
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.Sh SEE ALSO
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.Xr cd 1 ,
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.Xr csh 1 ,
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.Xr env 1 ,
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.Xr ex 1 ,
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.Xr login 1 ,
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.Xr printenv 1 ,
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.Xr sh 1 ,
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.Xr execve 2 ,
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.Xr execle 3 ,
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.Xr getbsize 3 ,
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.Xr getenv 3 ,
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.Xr setenv 3 ,
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.Xr setlocale 3 ,
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.Xr system 3 ,
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.Xr termcap 3 ,
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.Xr termcap 5
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.Sh HISTORY
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The
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.Nm
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manual page appeared in
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.At v7 .
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