xref: /netbsd-src/share/man/man7/environ.7 (revision 23c8222edbfb0f0932d88a8351d3a0cf817dfb9e)
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30.\"	@(#)environ.7	8.3 (Berkeley) 4/19/94
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32.Dd July 20, 2003
33.Dt ENVIRON 7
34.Os
35.Sh NAME
36.Nm environ
37.Nd user process environment
38.Sh SYNOPSIS
39.Ar extern char **environ ;
40.Sh DESCRIPTION
41An array of strings called the
42.Em environment
43is made available by
44.Xr execve 2
45when a process begins.
46By convention these strings have the form
47.Dq Ar name=value .
48The following names are used by various commands:
49.Bl -tag -width LIBC_DIAGASSERT
50.It Ev AUDIOCTLDEVICE
51The name of the audio control device to be used by
52.Xr audioctl 1 ,
53.Xr audioplay 1
54and
55.Xr audiorecord 1 .
56.It Ev AUDIODEVICE
57The name of the audio device to be used by
58.Xr audioplay 1
59and
60.Xr audiorecord 1 .
61.It Ev BLOCKSIZE
62The size of the block units used by several commands, most notably
63.Xr df 1 ,
64.Xr du 1
65and
66.Xr ls 1 .
67.Ev BLOCKSIZE
68may be specified in units of a byte by specifying a number,
69in units of a kilobyte by specifying a number followed by
70.Dq K
71or
72.Dq k ,
73in units of a megabyte by specifying a number followed by
74.Dq M
75or
76.Dq m
77and in units of a gigabyte by specifying a number followed
78by
79.Dq G
80or
81.Dq g .
82Sizes less than 512 bytes or greater than a gigabyte are ignored.
83.It Ev EXINIT
84A startup list of commands read by
85.Xr ex 1
86and
87.Xr vi 1 .
88.It Ev HOME
89A user's login directory, set by
90.Xr login 1
91from the password file
92.Xr passwd 5 .
93.It Ev LANG
94Default for all NLS categories.
95Only used if
96.Ev LC_ALL
97or the environment variable for a particular NLS category
98is not provided
99.Ev ( LC_COLLATE ,
100.Ev LC_CTYPE ,
101.Ev LC_MESSAGES ,
102.Ev LC_MONETARY ,
103.Ev LC_NUMERIC ,
104or
105.Ev LC_TIME ) .
106.It Ev LC_ALL
107Override for all NLS categories.
108If set, overrides the values of
109.Ev LC_COLLATE ,
110.Ev LC_CTYPE ,
111.Ev LC_MESSAGES ,
112.Ev LC_MONETARY ,
113.Ev LC_NUMERIC ,
114and
115.Ev LC_TIME .
116.It Ev LC_COLLATE
117NLS string-collation order information.
118.It Ev LC_CTYPE
119NLS character classification, case conversion, and other character attributes.
120.It Ev LC_MESSAGES
121NLS format for affirmative and negative responses.
122.It Ev LC_MONETARY
123NLS rules and symbols for formatting monetary numeric information.
124.It Ev LC_NUMERIC
125NLS rules and symbols for formatting nonmonetary numeric information.
126.It Ev LC_TIME
127NLS rules and symbols for formatting time and date information.
128.It Ev LIBC_DIAGASSERT
129Control how the
130.Fn _DIAGASSERT
131macro (from
132.Aq Pa assert.h )
133behaves once the assertion is raised.
134Refer to
135.Xr _DIAGASSERT 3
136for more information.
137.It Ev MALLOC_OPTIONS
138Control the behaviour of the
139.Fn malloc
140function.
141Refer to
142.Xr malloc 3
143for more information.
144.It Ev MIXERDEVICE
145The name of the audio mixer device to be used by
146.Xr mixerctl 1 .
147.It Ev PAGER
148The program used for paginating the output of several commands
149such as
150.Xr man 1 .
151If null or not set, the standard pagination program
152.Xr more 1
153will be used.
154.It Ev PATH
155The sequence of directories, separated by colons, searched by
156.Xr csh 1 ,
157.Xr sh 1 ,
158.Xr system 3 ,
159.Xr execvp 3 ,
160etc, when looking for an executable file.
161PATH is set to
162.Dq /usr/bin:/bin:/usr/pkg/bin:/usr/local/bin
163initially by
164.Xr login 1 .
165.It Ev PRINTER
166The name of the default printer to be used by
167.Xr lpr 1 ,
168.Xr lpq 1 ,
169and
170.Xr lprm 1 .
171.It Ev RCMD_CMD
172When using the
173.Xr rcmd 3
174function, this variable is used as the program to run instead of
175.Xr rcmd 1 .
176.It Ev SHELL
177The full pathname of the user's login shell.
178.It Ev TERM
179The kind of terminal for which output is to be prepared.
180This information is used by commands, such as
181.Xr nroff 1
182.\" or
183.\" .Xr plot 1
184which may exploit special terminal capabilities.
185See
186.Pa /usr/share/misc/termcap
187.Pq Xr termcap 5
188for a list of terminal types.
189.It Ev TERMCAP
190The string describing the terminal in TERM, or, if
191it begins with a '/', the name of the termcap file.
192See
193.Ev TERMPATH
194below,
195.Xr termcap 5 ,
196and
197.Xr termcap 3 .
198.It Ev TERMPATH
199A sequence of pathnames of termcap files, separated by colons or spaces,
200which are searched for terminal descriptions in the order listed.
201Having no
202.Ev TERMPATH
203is equivalent to a
204.Ev TERMPATH
205of
206.Dq Pa $HOME/.termcap:/usr/share/misc/termcap .
207.Ev TERMPATH
208is ignored if
209.Ev TERMCAP
210contains a full pathname.
211.It Ev TIMEFORMAT
212A
213.Xr strftime 3
214format string that may be used by programs such as
215.Xr dump 8
216for formatting timestamps.
217.It Ev TMPDIR
218The directory in which to store temporary files.
219Most applications use either
220.Pa /tmp
221or
222.Pa /var/tmp .
223Setting this variable will make them use another directory.
224.It Ev TZ
225The timezone to use when displaying dates.
226The normal format is a pathname relative to
227.Pa /usr/share/zoneinfo .
228For example, the command
229.Ic env TZ=US/Pacific date
230displays the current time in California.
231See
232.Xr tzset 3
233for more information.
234.It Ev USER
235The login name of the user.
236.El
237.Pp
238Further names may be placed in the environment by the
239.Ic export
240command and
241.Ar name=value
242arguments in
243.Xr sh 1 ,
244or by the
245.Ic setenv
246command if you use
247.Xr csh 1 .
248It is unwise to change certain
249.Xr sh 1
250variables that are frequently exported by
251.Pa .profile
252files, such as
253.Ev MAIL ,
254.Ev PS1 ,
255.Ev PS2 ,
256and
257.Ev IFS ,
258unless you know what you are doing.
259.Sh SEE ALSO
260.Xr audioctl 1 ,
261.Xr audioplay 1 ,
262.Xr audiorecord 1 ,
263.Xr csh 1 ,
264.Xr ex 1 ,
265.Xr login 1 ,
266.Xr man 1 ,
267.Xr more 1 ,
268.Xr sh 1 ,
269.Xr execve 2 ,
270.Xr _DIAGASSERT 3 ,
271.Xr execle 3 ,
272.Xr malloc 3 ,
273.Xr rcmd 3 ,
274.Xr system 3 ,
275.Xr termcap 3 ,
276.Xr audio 4 ,
277.Xr termcap 5 ,
278.Xr nls 7 ,
279.Xr dump 8
280.Sh HISTORY
281The
282.Nm
283manual page appeared in
284.Bx 4.2 .
285