plan9fox/sys/man/1/os

.TH OS 1
.SH NAME
os \- interface to host OS commands (drawterm only)
.SH SYNOPSIS
.B os
[
.B -b
] [
.B -m
.I mountpoint
] [
.BI -d " dir"
] [
.B -n
] [
.BI -N " level"
]
.I cmd
[
.IR arg ...
]
.SH DESCRIPTION
.I Os
uses a
.IR cmd (3)
device to execute a command,
.IR cmd ,
on a host system.
If the
.B -m
option is given,
.I os
uses the device at
.IR mountpoint ,
otherwise it is assumed to be at
.BR /mnt/term/cmd .
.PP
The
.B -d
option causes the command to run in directory
.IR dir ;
an error results and the command will not run if
.I dir
does not exist or is inaccessible.
The standard output and standard error of the command appear on the standard output
and standard error streams of the
.I os
command itself.
.I Os
copies the standard input to the remote command's standard input; redirect
.IR os 's
input to
.B /dev/null
if there is no input to the command.
.I Os
terminates when
.I cmd
does, and its exit status reflects the status of
.I cmd
(if available).
.PP
If the
.I os
command is killed or exits (eg, for lack of input and output),
the host's own process control operations are used to (attempt to) kill
.IR cmd ,
if it is still running.
The
.B -b
(background) option suppresses that behaviour.
.PP
The
.B -n
option causes
.I cmd
to run with less than normal priority (`nice').
The
.B -N
option sets low priority to a particular
.I level
from 1 to 3.
.SH FILES
.B /mnt/term/cmd/clone
.SH SOURCE
.B /sys/src/cmd/os.c
.SH "SEE ALSO"
.IR rcpu (1),
.IR cmd (3)
.SH DIAGNOSTICS
The exit status of
.I os
reflects any error that occurs when starting
.I cmd
and, if it starts successfully, the status of
.I os
is the exit status of
.IR cmd .