xref: /freebsd/usr.bin/printenv/printenv.1 (revision 17d6c636720d00f77e5d098daf4c278f89d84f7b)
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34.\"	@(#)printenv.1	8.1 (Berkeley) 6/6/93
35.\" $FreeBSD$
36.\"
37.Dd June 6, 1993
38.Dt PRINTENV 1
39.Os
40.Sh NAME
41.Nm printenv , env
42.Nd print out the environment, set and print environment
43.Sh SYNOPSIS
44.Nm
45.Op Ar name
46.Nm env
47.Op Fl
48.Op Fl i
49.Op Ar name Ns = Ns Ar value ...
50.Op Ar command
51.Sh DESCRIPTION
52.Nm Printenv
53prints out the names and values of the variables in the environment,
54with one name/value pair per line.
55If
56.Ar name
57is specified, only
58its value is printed.
59.Pp
60If a
61.Ar name
62is specified and it is not defined in the environment,
63.Nm
64returns exit status 1, else it returns status 0.
65.Pp
66Some shells may provide a builtin
67.Nm
68command which is similar or identical to this utility.
69Consult the
70.Xr builtin 1
71manual page.
72.Pp
73.Nm Env
74executes
75.Ar command
76after modifying the environment as
77specified on the command line.
78The option
79.Ar name Ns = Ns Ar value
80specifies
81an environment variable,
82.Ar name  ,
83with a value of
84.Ar value  .
85.Pp
86The options are as follows:
87.Bl -tag -width indent
88.It Fl i
89Execute the
90.Ar command
91with only those environment values specified.
92The environment inherited
93by
94.Nm env
95is ignored completely.
96.It Fl
97Identical to the
98.Fl i
99option, available for backward compatibility.
100.El
101.Pp
102If no command is specified,
103.Nm env
104prints out the names and values
105of the variables in the environment, with one name/value pair per line.
106.Pp
107.Nm env
108is sometimes useful with the
109.Dq Li #!
110construct (see
111.Xr execve 2 ) .
112The only difference between
113.Dq Li #!/usr/local/bin/foo
114and
115.Dq Li "#!/usr/bin/env\ /usr/local/bin/foo"
116is that the latter works even if
117.Pa /usr/local/bin/foo
118is itself interpreted.
119Using
120.Nm env
121this way also allows one to reference
122.Pa foo
123without the path,
124as well as set up the environment as desired.
125.Sh SEE ALSO
126.Xr csh 1 ,
127.Xr sh 1 ,
128.Xr execvp 3 ,
129.Xr environ 7
130.Sh HISTORY
131The
132.Nm
133command appeared in
134.Bx 3.0 .
135.Sh BUGS
136.Nm Env
137doesn't handle commands with equal (``='') signs in their
138names, for obvious reasons.
139