rexec(1)						      General Commands Manual							  rexec(1)

NAME

       remsh, rexec - execute from a remote shell

SYNOPSIS

       host username] command
	     host username] command

       host username] command

   In Kerberos V5 Network Authentication Environments:
       host username] realm] command
	     host username] realm] command

DESCRIPTION

       connects  to a specified host and executes a specified command.	The host name can be either the official name or an alias as understood by
       (see gethostent(3N) and hosts(4)).  copies its standard input to the remote command, the standard output of the remote command to its stan-
       dard  output and the standard error of the remote command to its standard error Hangup, interrupt, quit, terminate, and broken pipe signals
       are propagated to the remote command.  exits when the sockets associated with and of the remote command are closed.  This means	that  nor-
       mally terminates when the remote command does (see remshd(1M)).

       By default, uses the following path when executing the specified command:

       uses  the  default  remote  login shell with the option to execute the remote command.  If the default remote shell is csh, csh sources the
       remote file before the command.	cannot be used to run commands that require a terminal interface (such as  or  commands  that  read  their
       standard error (such as In such cases, use or instead (see rlogin(1) and telnet(1)).

       The  remote  account  name  used  is the same as your local account name, unless you specify a different remote name with the option.  This
       remote account name must be equivalent to the originating account.  In addition, the remote host account name must also	conform  to  other
       rules,  which differ depending upon whether the remote host is operating in a Kerberos V5 Network Authentication, i.e., secure environment,
       or not.

       In a non-secure, or traditional environment, the remote account name must be equivalent to the originating account; no  provision  is  made
       for  specifying	a password with a command.  For more details about hosts and how to specify them, see hosts.equiv(4).  The files inspected
       by on the remote host are and (see remshd(1M)).

       In a Kerberos V5 Network Authentication environment, the local host must be successfully authenticated before the remote  account  name	is
       checked	for  proper authorization.  The authorization mechanism is dependent on the command line options used to invoke on the remote host
       (i.e., For more information on Kerberos authentication and authorization see the Secure Internet Services man page, sis(5) and remshd(1M).

       Although Kerberos authentication and authorization may apply, the Kerberos mechanism is applied to the command or to its response.  All the
       information that is transferred between the local and remote host is still sent in cleartext over the network.

       In a secure or Kerberos V5-based environment, the following command line options are available:

	      Forward the ticket granting ticket (TGT) to the remote system.  The TGT
			  is not forwardable from that remote system.

	      Forward the TGT to the remote system and have it forwardable from
			  there to another remote system.  The option and option are mutually exclusive.

	      Obtain tickets from the remote host in the
			  specified realm instead of the remote host's default realm as specified in the configuration file

	      Disable Kerberos authentication.

       The Kerberos authentication and authorization mechanism and the above Kerberos specific options are not supported in IPv6 enabled systems.

       If  command,  is not specified, instead of executing a single command, you will be logged in on the remote host using (see rlogin(1)).  Any
       options typed in on the command line are transmitted to If no command and the option are specified, will be invoked with to  indicate  that
       Kerberos  authentication  (or  secure  access)  is  not necessary. This means that if a password is requested, the password will be sent in
       cleartext.  If command is specified, options specific to are ignored by

       By default, reads its standard input and sends it to the remote command because has no way to determine whether the remote command requires
       input.	The option redirects standard input to from This is useful when running a shell script containing a command, since otherwise remsh
       may use input not intended for it.  The option is also useful when running in the background from a job control shell, or Otherwise,  stops
       and  waits  for	input  from the terminal keyboard for the remote command.  automatically redirects its input from when jobs are run in the
       background.

       Host names for remote hosts can also be commands (linked to in the directory If this directory is specified in  the  environment  variable,
       you can omit For example, if is the name of a remote host, is linked to and if is in your search path, the command

       executes command on and the command

       is equivalent to

       The  command  works in the same way as except that it uses the library routine and for command execution (see rexec(3N) and rexecd(1M)) and
       does not support Kerberos authentication.  prompts for a password before executing the command instead of  using  for  authentication.	It
       should be used in instances where a password to a remote account is known but there are insufficient permissions for

EXAMPLES

       Shell metacharacters that are not quoted are interpreted on the local host; quoted metacharacters are interpreted on the remote host.  Thus
       the command line:

       appends the remote file to the local file while the command line

       appends to the remote file

       If the remote shell is the following command line sets up the environment for the remote command before executing the remote command:

       The throws away error messages generated by executing when stdin and stdout are not a terminal.

       The following command line runs in the background on the local system, and the output of the remote command comes to  your  terminal  asyn-
       chronously:

       The background completes when the remote command does.

       The following command line causes to return immediately without waiting for the remote command to complete:

       (See remshd(1M) and sh(1)).  If your login shell on the remote system is csh, use the following form instead:

RETURN VALUE

       If  fails  to  set up the secondary socket connection, it returns 2.  If it fails in some other way, it returns 1.  If it fully succeeds in
       setting up a connection with it returns 0 once the remote command has completed.  Note that the return value of bears no  relation  to  the
       return value of the remote command.

DIAGNOSTICS

       Besides	the  errors listed below, errors can also be generated by the library functions and In the case of IPv6 systems, the library func-
       tions and are replaced by and respectively, and can generate errors (see rcmd(3N) and rcmd_af(3N)).  These errors are preceded by the  name
       of the library function that generated them.  can produce the following diagnostic messages:

	      There are two authentication mechanisms used by
		     One  authentication  mechanism  is  based on Kerberos and the other is not.  The type of authentication mechanism is obtained
		     from a system file which is updated by (see inetsvcs_sec(1M)).  If the system file  does  not  contain  known  authentication
		     types, the above error is displayed.

	      Error in executing
		     is  executed  when  the user does not specify any commands to be executed).  This is followed by the error message specifying
		     why the execution failed.

	      The ``shell'' service specification is not present in the
		     file.

	      cannot establish secondary socket connection for

	      Error in executing system call.
		     Appended to this error is a message specifying the cause of the failure.

	      Check with the system administrator
		     to see if your entry in the password file has been deleted by mistake.

       Kerberos-specific errors are listed in sis(5).

WARNINGS

       For security reasons, the and files should exist, even if empty, and they should be readable and writable only by  the  owner.	Note  also
       that all information, including any passwords asked for, is passed unencrypted between the two hosts.

       If is run with an interactive command, it hangs.

DEPENDENCIES

       is the same service as on BSD systems.  The name was changed due to a conflict with the existing System V command (restricted shell).

AUTHOR

       was developed by the University of California, Berkeley.

FILES

       for version of the command invoked only with hostname

SEE ALSO

       rlogin(1), remshd(1M), rexecd(1M), inetsvcs_sec(1M), gethostent(3N), rcmd(3N), rcmd_af(3N), rexec(3N), hosts.equiv(4), hosts(4).

																	  rexec(1)