usr.bin/env/env.1

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.\" From @(#)printenv.1	8.1 (Berkeley) 6/6/93
.\" From FreeBSD: src/usr.bin/printenv/printenv.1,v 1.17 2002/11/26 17:33:35 ru Exp
.\" $FreeBSD$
.\"
.Dd May 12, 2003
.Dt ENV 1
.Os
.Sh NAME
.Nm env
.Nd set and print environment
.Sh SYNOPSIS
.Nm
.Op Fl i
.Op Ar name Ns = Ns Ar value ...
.Op Ar utility Op Ar argument ...
.Sh DESCRIPTION
The
.Nm
utility executes another
.Ar utility
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 utility
with only those environment variables specified.
The environment inherited
by
.Nm
is ignored completely.
.El
.Pp
If no
.Ar utility
is specified,
.Nm
prints out the names and values
of the variables in the environment, with one name/value pair per line.
.Pp
The
.Nm
utility is sometimes useful with the
.Ql #!
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
this way also allows one to reference
.Pa foo
without the path,
as well as set up the environment as desired.
.Sh ENVIRONMENT
The
.Nm
utility uses the
.Ev PATH
environment variable to locate the requested
.Ar utility
if the name contains no
.Ql /
characters.
.Sh DIAGNOSTICS
.Ex -std
An exit status of 126 indicates that
.Ar utility
was found, but could not be executed.
An exit status of 127 indicates that
.Ar utility
could not be found.
.Sh COMPATIBILITY
The
.Nm
utility accepts the
.Fl
option as a synonym for
.Fl i .
.Sh SEE ALSO
.Xr printenv 1 ,
.Xr sh 1 ,
.Xr execvp 3 ,
.Xr environ 7
.Sh STANDARDS
The
.Nm
utility conforms to
.St -p1003.1-2001 .
.\".Sh HISTORY
.\"The
.\".Nm
.\"command appeared in
.\".Bx 3.0 .
.Sh BUGS
The
.Nm
utility does not handle utility arguments with equal signs
.Pq Ql =
in their names, for obvious reasons.