path: root/sshexec.1

.TH SSHEXEC 1 sshexec

.SH NAME
sshexec - run a command through ssh(1) with normal command syntax

.SH SYNOPSIS
.B sshexec
.RB [ {
.RI [\fBssh=\fP ssh-command ]
.RI [\fBdir=\fP directory ]
.RB [ cd= ( strict | lax )]
.RB [[\fIfd\fP]{ > , >> , >| , < , <> }[ & ] = \fIfile\fP]
.BR } ]
.RI [ ssh-option ]\ ...\,
.I destination
.I command
.RI [ argument ]\ ...\,

.SH DESCRIPTION
The
.B sshexec
utility is a wrapper for SSH that makes it easy to run commands
directly in the SSH command.

.B sshexec
passes any argument after
.B }
to
.I ssh-command
.RB ( ssh
if not specified), but it
rewrites
.I command
and the
.IR argument s
to one argument that can be passed into
.BR ssh (1)
to describe each argument as separate arguments.
It may also rewrite
.I destination
to remove information that's not supported by
.BR ssh (1)
and inserts extra arguments after it
(it may also add a
.B --
argument immediately before
.IR destination )
to cause the remote shell it change working directory to
.IR directory ,
if specified, and execute the provided
.I command
and
.IR argument s
as a regular command rather than as shell code joined
by together by spaces.

.SH OPTIONS
.B sshexec
options may be placed at the very beginning enclosed with
the arguments
.B {
and
.BR } .
.B sshexec
options, if any, shall be placed in the same
.B {
.BR } -group.
Any other option will be passed as is to the
.BR ssh (1)
utility or
.IR ssh-command .
The
.B sshexec
utility has a build it list of options recognised by the
.BR ssh (1)
utility and will not allow anything matching this list.
The
.B sshexec
utility does not allow mixing options and operands: no
option may be placed after
.IR destination ,
such options will be treated as the
.I command
or an
.IR argument .
.PP
The following
.B sshexec
options are supported:
.TP
.BI ssh= ssh-command
Instead of looking for
.B ssh
in
.IR PATH ,
the
.B sshexec
utility shall use
.IR ssh-command ,
which it will look for in
.I PATH
if it is only a file name (does not contain a slash
.RB ( / )).
.TP
.BI dir= directory
In the remote, change working directory to
.I directory
before executing
.IR command .
.TP
.B cd=strict
Fail without executing the
.I command
if it's not possible to set
.I directory
as the remote working directory.
.TP
.B cd=lax
Continue (but warn) executing the
.I command
even if it's not possible to set
.I directory
as the remote working directory.
.TP
.IB \fR[\fPfd\fP]\fP >= file
After changing working directory (assuming one is specified),
create or truncate the specified
.I file
and open it for writing, using file descriptor number
.IR fd .
(Default
.I fd
is 1 (standard output).)
.TP
.IB \fR[\fPfd\fP]\fP >>= file
After changing working directory (assuming one is specified),
create the specified
.I file
if it does not exist and open it for writing in
append-mode, using file descriptor number
.IR fd .
(Default
.I fd
is 1 (standard output).)
.TP
.IB \fR[\fPfd\fP]\fP >|= file
After changing working directory (assuming one is specified),
create the specified
.IR file ,
but fail if it already exists, and open it for writing,
using file descriptor number
.IR fd .
(Default
.I fd
is 1 (standard output).)
.TP
.IB \fR[\fPfd\fP]\fP <= file
After changing working directory (assuming one is specified),
open the specified
.IR file ,
for reading, using file descriptor number
.IR fd .
(Default
.I fd
is 0 (standard input).)
.TP
.IB \fR[\fPfd\fP]\fP <>= file
After changing working directory (assuming one is specified),
open the specified
.IR file ,
for reading and writing, creating it if it does not
already exist, using file descriptor number
.IR fd .
(Default
.I fd
is 0 (standard input).)
.TP
.IB \fR[\fPfd\fP]\fP \fR{\fP>\fP,\fP>>\fP,\fP>|\fP}\fP&= file
Duplicate the file descriptor
.I fd
giving the new file descriptor the number
.IR file .
(Default
.I fd
is 1 (standard output).)
.TP
.IB \fR[\fPfd\fP]\fP \fR{\fP>\fP,\fP>>\fP,\fP>|\fP}\fP&=-
Close the file descriptor
.IR fd .
(Default
.I fd
is 1 (standard output).)
.TP
.IB \fR[\fPfd\fP]\fP \fR{\fP<\fP,\fP<>\fP}\fP&= file
Duplicate the file descriptor
.I fd
giving the new file descriptor the number
.IR file .
(Default
.I fd
is 0 (standard input).)
.TP
.IB \fR[\fPfd\fP]\fP \fR{\fP<\fP,\fP<>\fP}\fP&=-
Close the file descriptor
.IR fd .
(Default
.I fd
is 0 (standard input).)

.SH OPERANDS
The following operands are supported:
.TP
.I destination
The destination to connect and log into. It shall be either in
the form
.RI [ user\fP\fB@ ] hostname [\fB:\fP directory ]
or in the form
.BR ssh [ exec ] :// [\fIuser @ ]\fIhostname\fP[ : \fIport\fP][ / \fIdirectory\fP].

.I user
shall be the name of the remote user. If not specified,
the name of the local user running the utility will be used.

.I hostname
shall be the address to the remote machine.

.I port
shall be the port or service name for the port to
connect to on the remote machine.

.I directory
shall be directory to change the remote working directory.
This is an alternative to (with the exact same behaviour)
to the
.B dir
option and cannot be combined with it.
.TP
.IR command \ [ argument ]\ ...\,
Whereas the
.BR ssh (1)
utility would simply join the
.I command
and
.I argument
arguments with a space between each of them as pass it
to the remote shell for execution, the
.B sshexec
utility forces the remote shell to treat each of the
as separate arguments and cause the shell to executing
them as a non-builtin command.

.I command
must not contain an equals sign
.RB ( = )
or be just a dash
.RB (\(dq - \(dq).

.SH STDIN
The
.B sshexec
utility itself does not use the standard input.

.SH INPUT FILES
None.

.SH ENVIRONMENT VARIABLES
The following environment variables affects the execution of
.BR sshexec :
.TP
.SH PATH
Default. See to the Base Definitions volume of POSIX.1-2017, Section 8.3, Other Environment Variables.
This environment variable affects where the
.B sshexec
utility can find the
.BR ssh (1)
utility or
.IR ssh-command .
.PP
Other environment variables may affect the execution of the
.BR ssh (1)
utility.

.SH ASYNCHRONOUS EVENTS
Default.

.SH STDOUT
The
.B sshexec
utility itself does not use the standard output.

.SH STDERR
The standard error is used for diagnostic messages in the
.B sshexec
utility itself.

.SH OUTPUT FILES
None.

.SH EXTENDED DESCRIPTION
None.

.SH EXIT STATUS
The
.B sshexec
utility exits with the exit status of the
.BR ssh (1)
utility or with 255 if an error occurred.

.SH CONSEQUENCES OF ERRORS
Default.

.SH APPLICATION USAGE
None.

.SH EXAMPLES
None.

.SH RATIONALE
The restrictions on
.I command
is in place to avoid unspecified behaviour.

.SH NOTES
None.

.SH BUGS
The remote shell must be sufficiently similar to
.BR sh (1posix).
Namely, it must support the
.B cd
builtin command and the commands
.B exec
and
.B printf
is expected by POSIX. Additionally, it must support
.BR \(dq$(\ )\(dq ,
.BR \(aq\ \(aq ,
and
.BR && ,
and argument separation with the SP character.
The remote shell must also not treat any alphanumeric
character, underscore
.RB ( _ )
or slash
.RB ( / )
as special characters.

.SH FUTURE DIRECTIONS
None.

.SH SEE ALSO
.BR ssh (1)

.SH AUTHORS
Mattias Andrée
.RI < m@maandree.se >