1.\" Copyright (c) 1983, 1990, 1993 2.\" The Regents of the University of California. All rights reserved. 3.\" 4.\" Redistribution and use in source and binary forms, with or without 5.\" modification, are permitted provided that the following conditions 6.\" are met: 7.\" 1. Redistributions of source code must retain the above copyright 8.\" notice, this list of conditions and the following disclaimer. 9.\" 2. Redistributions in binary form must reproduce the above copyright 10.\" notice, this list of conditions and the following disclaimer in the 11.\" documentation and/or other materials provided with the distribution. 12.\" 3. Neither the name of the University nor the names of its contributors 13.\" may be used to endorse or promote products derived from this software 14.\" without specific prior written permission. 15.\" 16.\" THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 17.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 18.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 19.\" ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 20.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 21.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 22.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 23.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 24.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 25.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 26.\" SUCH DAMAGE. 27.\" 28.\" @(#)environ.7 8.3 (Berkeley) 4/19/94 29.\" $FreeBSD$ 30.\" 31.Dd August 5, 2020 32.Dt ENVIRON 7 33.Os 34.Sh NAME 35.Nm environ 36.Nd user environment 37.Sh SYNOPSIS 38.Ar extern char **environ ; 39.Sh DESCRIPTION 40An array of strings, called the 41.Ar environment 42is made available to each process by 43.Xr execve 2 44when a process begins. 45By convention these strings have the form 46.Va name Ns No = Ns Ar value , 47and are referred to as 48.Dq environment variables . 49A process can query, update, and delete these strings using the 50.Xr getenv 3 , 51.Xr setenv 3 , 52and 53.Xr unsetenv 3 54functions, respectively. 55The shells also provide commands to manipulate the environment; 56they are described in the respective shell manual pages. 57.Pp 58What follows is a list of environment variables typically 59seen on a 60.Ux 61system. 62It includes only those variables that a user can expect to see during their 63day-to-day use of the system, and is far from complete. 64Environment variables specific to a particular program or library function 65are documented in the 66.Sx ENVIRONMENT 67section of the appropriate manual page. 68.Sh ENVIRONMENT 69.Bl -tag -width LD_LIBRARY_PATH 70.It Ev BLOCKSIZE 71The size of the block units used by several disk-related commands, 72most notably 73.Xr df 1 , 74.Xr du 1 75and 76.Xr ls 1 . 77.Ev BLOCKSIZE 78may be specified in units of a byte by specifying a number, 79in units of a kilobyte by specifying a number followed by 80.Ql K 81or 82.Ql k , 83in units of a megabyte by specifying a number followed by 84.Ql M 85or 86.Ql m , 87and in units of a gigabyte by specifying a number followed 88by 89.Ql G 90or 91.Ql g . 92Sizes less than 512 bytes or greater than a gigabyte are ignored. 93This variable is processed by the 94.Xr getbsize 3 95function. 96.It Ev COLUMNS 97The user's preferred width in column positions for the terminal. 98Utilities such as 99.Xr ls 1 100and 101.Xr who 1 102use this to format output into columns. 103If unset or empty, utilities will use an 104.Xr ioctl 2 105call to ask the terminal driver for the width. 106.It Ev EDITOR 107Default editor name. 108.It Ev EXINIT 109A startup list of commands read by 110.Xr ex 1 111and 112.Xr vi 1 . 113.It Ev HOME 114A user's login directory, set by 115.Xr login 1 116from the password file 117.Xr passwd 5 . 118.It Ev LANG 119This variable configures all programs which use 120.Xr setlocale 3 121to use the specified locale unless the 122.Ev LC_* 123variables are set. 124.It Ev LC_ALL 125Overrides the values of 126.Ev LC_COLLATE , 127.Ev LC_CTYPE , 128.Ev LC_MESSAGES , 129.Ev LC_MONETARY , 130.Ev LC_NUMERIC , 131.Ev LC_TIME 132and 133.Ev LANG . 134.It Ev LC_COLLATE 135Locale to be used for ordering of strings. 136.It Ev LC_CTYPE 137Locale to be used for character classification 138(letter, space, digit, etc.) and for interpreting byte sequences as 139multibyte characters. 140.It Ev LC_MESSAGES 141Locale to be used for diagnostic messages. 142.It Ev LC_MONETARY 143Locale to be used for interpreting monetary input 144and formatting output. 145.It Ev LC_NUMERIC 146Locale to be used for interpreting numeric input and 147formatting output. 148.It Ev LC_TIME 149Locale to be used for interpreting dates input and 150for formatting output. 151.It Ev MAIL 152The location of the user's 153mailbox instead of the default in /var/mail, 154used by 155.Xr mail 1 , 156.Xr sh 1 , 157and many other mail clients. 158.It Ev MANPATH 159The sequence of directories, separated by colons, searched by 160.Xr man 1 161when looking for manual pages. 162.It Ev NLSPATH 163List of directories to be searched for the message catalog referred to by 164.Ev LC_MESSAGES . 165See 166.Xr catopen 3 . 167.It Ev PAGER 168Default paginator program. 169The program specified by this variable is used by 170.Xr mail 1 , 171.Xr man 1 , 172.Xr ftp 1 , 173etc, to display information which is longer than the current display. 174.It Ev PATH 175The sequence of directories, separated by colons, searched by 176.Xr csh 1 , 177.Xr sh 1 , 178.Xr system 3 , 179.Xr execvp 3 , 180etc, when looking for an executable file. 181.Ev PATH 182is set to ``/usr/bin:/bin'' initially by 183.Xr login 1 . 184.It Ev POSIXLY_CORRECT 185When set to any value, this environment variable modifies the behaviour 186of certain commands to (mostly) execute in a strictly POSIX-compliant manner. 187.It Ev PRINTER 188The name of the default printer to be used by 189.Xr lpr 1 , 190.Xr lpq 1 , 191and 192.Xr lprm 1 . 193.It Ev PWD 194The current directory pathname. 195.It Ev SHELL 196The full pathname of the user's login shell. 197.It Ev TERM 198The kind of terminal for which output is to be prepared. 199This information is used by commands, such as 200.Xr nroff 1 Pq Pa ports/textproc/groff 201or 202.Xr plot 1 203which may exploit special terminal capabilities. 204See 205.Pa /usr/share/misc/termcap 206.Pq Xr termcap 5 207for a list of terminal types. 208.It Ev TERMCAP 209The string describing the terminal in 210.Ev TERM , 211or, if 212it begins with a '/', the name of the termcap file. 213See 214.Ev TERMPATH 215below, and 216.Xr termcap 5 . 217.It Ev TERMPATH 218A sequence of pathnames of termcap files, separated by colons or spaces, 219which are searched for terminal descriptions in the order listed. 220Having 221no 222.Ev TERMPATH 223is equivalent to a 224.Ev TERMPATH 225of 226.Pa $HOME/.termcap:/etc/termcap . 227.Ev TERMPATH 228is ignored if 229.Ev TERMCAP 230contains a full pathname. 231.It Ev TMPDIR 232The directory in which to store temporary files. 233Most applications use either 234.Pa /tmp 235or 236.Pa /var/tmp . 237Setting this variable will make them use another directory. 238.It Ev TZ 239The timezone to use when displaying dates. 240The normal format is a pathname relative to 241.Pa /usr/share/zoneinfo . 242For example, the command 243.Pp 244.Dl env TZ=America/Los_Angeles date 245.Pp 246displays the current time in California. 247See 248.Xr tzset 3 249for more information. 250.It Ev USER 251The login name of the user. 252It is recommended that portable applications use 253.Ev LOGNAME 254instead. 255.El 256.Pp 257Further names may be placed in the environment by the 258.Ic export 259command and 260.Ar name=value 261arguments in 262.Xr sh 1 , 263or by the 264.Ic setenv 265command if you use 266.Xr csh 1 . 267It is unwise to change certain 268.Xr sh 1 269variables that are frequently exported by 270.Pa .profile 271files, such as 272.Ev MAIL , 273.Ev PS1 , 274.Ev PS2 , 275and 276.Ev IFS , 277unless you know what you are doing. 278.Pp 279The current environment variables can be printed with 280.Xr env 1 , 281.Xr set 1 282or 283.Xr printenv 1 284in 285.Xr sh 1 286and 287.Xr env 1 , 288.Xr printenv 1 289or the 290.Cm printenv 291built-in command in 292.Xr csh 1 . 293.Sh SEE ALSO 294.Xr cd 1 , 295.Xr csh 1 , 296.Xr env 1 , 297.Xr ex 1 , 298.Xr login 1 , 299.Xr printenv 1 , 300.Xr sh 1 , 301.Xr execve 2 , 302.Xr execle 3 , 303.Xr getbsize 3 , 304.Xr getenv 3 , 305.Xr setenv 3 , 306.Xr setlocale 3 , 307.Xr system 3 , 308.Xr termcap 3 , 309.Xr termcap 5 310.Sh HISTORY 311The 312.Nm 313manual page appeared in 314.At v7 . 315