HardenedBSD/usr.bin/printenv/printenv.1
2001-07-05 06:35:03 +00:00

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.\" @(#)printenv.1 8.1 (Berkeley) 6/6/93
.\" $FreeBSD$
.\"
.Dd June 6, 1993
.Dt PRINTENV 1
.Os
.Sh NAME
.Nm printenv , env
.Nd print out the environment, set and print environment
.Sh SYNOPSIS
.Nm
.Op Ar name
.Nm env
.Op Fl
.Op Fl i
.Op Ar name Ns = Ns Ar value ...
.Op Ar command
.Sh DESCRIPTION
.Nm Printenv
prints out the names and values of the variables in the environment,
with one name/value pair per line.
If
.Ar name
is specified, only
its value is printed.
.Pp
If a
.Ar name
is specified and it is not defined in the environment,
.Nm
returns exit status 1, else it returns status 0.
.Pp
Some shells may provide a builtin
.Nm
command which is similar or identical to this utility.
Consult the
.Xr builtin 1
manual page.
.Pp
.Nm Env
executes
.Ar command
after modifying the environment as
specified on the command line.
The option
.Ar name Ns = Ns Ar value
specifies
an environment variable,
.Ar name ,
with a value of
.Ar value .
.Pp
The options are as follows:
.Bl -tag -width indent
.It Fl i
Execute the
.Ar command
with only those environment values specified.
The environment inherited
by
.Nm env
is ignored completely.
.It Fl
Identical to the
.Fl i
option, available for backward compatibility.
.El
.Pp
If no command is specified,
.Nm env
prints out the names and values
of the variables in the environment, with one name/value pair per line.
.Pp
.Nm env
is sometimes useful with the
.Dq Li #!
construct (see
.Xr execve 2 ) .
The only difference between
.Dq Li #!/usr/local/bin/foo
and
.Dq Li "#!/usr/bin/env\ /usr/local/bin/foo"
is that the latter works even if
.Pa /usr/local/bin/foo
is itself interpreted.
Using
.Nm env
this way also allows one to reference
.Pa foo
without the path,
as well as set up the environment as desired.
.Sh SEE ALSO
.Xr csh 1 ,
.Xr sh 1 ,
.Xr execvp 3 ,
.Xr environ 7
.Sh HISTORY
The
.Nm
command appeared in
.Bx 3.0 .
.Sh BUGS
.Nm Env
doesn't handle commands with equal (``='') signs in their
names, for obvious reasons.