freebsd-dev/usr.bin/nohup/nohup.1
Mike Barcroft e896ec1ef5 o Integrate security enhancements from OpenBSD.
- Don't assume environment variable HOME is not NULL.
o Integrate standards compliance from NetBSD.
  - Allow -- before the command.
  - Blocking SIGQUIT isn't standards compliant.
  - Proper exit(3) levels.
  - Actually append to nohup.out (as documented and required
    by standard) instead of clobbering it.
o Remove some FreeBSD specific access(2) cruft (relating to
  incorrect appending).
o Document the fact that two or more instances of nohup can
  append to the same file.
o Constify; Staticize functions; Set WARNS?=2

Reviewed by:	bde
Approved by:	des
Obtained from:	NetBSD, OpenBSD
MFC after:	9 days
2001-07-19 21:25:10 +00:00

119 lines
3.4 KiB
Groff

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.\" @(#)nohup.1 8.1 (Berkeley) 6/6/93
.\" $FreeBSD$
.\"
.Dd June 6, 1993
.Dt NOHUP 1
.Os
.Sh NAME
.Nm nohup
.Nd invoke a command immune to hangups
.Sh SYNOPSIS
.Nm
.Op Ar --
.Ar command
.Op Ar arguments
.Sh DESCRIPTION
The
.Nm
utility invokes
.Ar command
with its
.Ar arguments
and at this time sets the signal
.Dv SIGHUP
to be ignored.
If the standard output is a terminal, the standard output is
appended to the file
.Pa nohup.out
in the current directory.
If standard error is a terminal, it is directed to the same place
as the standard output.
.Pp
Some shells may provide a builtin
.Nm
command which is similar or identical to this utility.
Consult the
.Xr builtin 1
manual page.
.Sh ENVIRONMENT
The following variable is utilized by
.Nm :
.Bl -tag -width flag
.It Ev HOME
If the output file
.Pa nohup.out
cannot be created in the current directory, the
.Nm
utility uses the directory named by
.Ev HOME
to create the file.
.El
.Sh DIAGNOSTICS
The
.Nm
utility exits with one of the following values:
.Bl -tag -width Ds
.It 126
The
.Ar command
was found, but could not be invoked.
.It 127
The
.Ar command
could not be found or an error occurred in
.Nm .
.El
.Pp
Otherwise, the exit status of
.Nm
will be that of
.Ar command .
.Sh SEE ALSO
.Xr builtin 1 ,
.Xr csh 1 ,
.Xr signal 3
.Sh STANDARDS
The
.Nm
utility is expected to be
.St -p1003.2
compatible.
.Sh BUGS
Two or more instances of
.Nm
can append to the same file, which makes for a confusing output.