UUX(1P)                                             POSIX Programmer's Manual                                            UUX(1P)



PROLOG
       This  manual  page is part of the POSIX Programmer's Manual.  The Linux implementation of this interface may differ (con-
       sult the corresponding Linux manual page for details of Linux behavior), or the  interface  may  not  be  implemented  on
       Linux.

NAME
       uux - remote command execution

SYNOPSIS
       uux [-np] command-string

       uux [-jnp] command-string


DESCRIPTION
       The uux utility shall gather zero or more files from various systems, execute a shell pipeline (see Shell Commands ) on a
       specified system, and then send the standard output of the command to a file on a specified system. Only the  first  com-
       mand  of a pipeline can have a system-name! prefix. All other commands in the pipeline shall be executed on the system of
       the first command.

       The following restrictions are applicable to the shell pipeline processed by uux:

        * In gathering files from different systems, pathname expansion shall not be performed by uux. Thus, a request such as:


          uux "c99 remsys!~/*.c"

       would attempt to copy the file named literally *.c to the local system.

        * The redirection operators ">>", "<<", ">|", and ">&" shall not be accepted. Any use  of  these  redirection  operators
          shall cause this utility to write an error message describing the problem and exit with a non-zero exit status.

        * The  reserved word ! cannot be used at the head of the pipeline to modify the exit status. (See the command-string op-
          erand description below.)

        * Alias substitution shall not be performed.

       A filename can be specified as for uucp; it can be an absolute pathname, a pathname preceded by ~ name (which is replaced
       by  the corresponding login directory), a pathname specified as ~/ dest ( dest is prefixed by the public directory called
       PUBDIR; the actual location of PUBDIR is implementation-defined), or a simple filename (which is prefixed by uux with the
       current directory). See uucp for the details.

       The  execution  of  commands  on  remote systems shall take place in an execution directory known to the uucp system. All
       files required for the execution shall be put into this directory unless they already reside on that machine.  Therefore,
       the  application  shall  ensure  that  non-local  filenames (without path or machine reference) are unique within the uux
       request.

       The uux utility shall attempt to get all files to the execution system. For files that are output files, the  application
       shall ensure that the filename is escaped using parentheses.

       The remote system shall notify the user by mail if the requested command on the remote system was disallowed or the files
       were not accessible. This notification can be turned off by the -n option.

       Typical implementations of this utility require a communications line configured to use the Base  Definitions  volume  of
       IEEE Std 1003.1-2001,  Chapter  11,  General  Terminal  Interface, but other communications means may be used. On systems
       where there are no available communications means (either temporarily or permanently), this utility shall write an  error
       message describing the problem and exit with a non-zero exit status.

       The uux utility cannot guarantee support for all character encodings in all circumstances. For example, transmission data
       may be restricted to 7 bits by the underlying network, 8-bit data and filenames need not be portable to  non-internation-
       alized  systems,  and  so  on.  Under  these  circumstances,  it  is  recommended  that  only  characters  defined in the
       ISO/IEC 646:1991 standard International Reference Version (equivalent to ASCII) 7-bit range of  characters  be  used  and
       that only characters defined in the portable filename character set be used for naming files.

OPTIONS
       The uux utility shall conform to the Base Definitions volume of IEEE Std 1003.1-2001, Section 12.2, Utility Syntax Guide-
       lines.

       The following options shall be supported:

       -p     Make the standard input to uux the standard input to the command-string.

       -j     Write the job identification string to standard output. This job identification can be used by  uustat  to  obtain
              the status or terminate a job.

       -n     Do not notify the user if the command fails.


OPERANDS
       The following operand shall be supported:

       command-string

              A  string  made  up of one or more arguments that are similar to normal command arguments, except that the command
              and any filenames can be prefixed by system-name!. A null system-name shall be interpreted as the local system.


STDIN
       The standard input shall not be used unless the '-' or -p option is specified; in those cases, the standard  input  shall
       be made the standard input of the command-string.

INPUT FILES
       Input files shall be selected according to the contents of command-string.

ENVIRONMENT VARIABLES
       The following environment variables shall affect the execution of uux:

       LANG   Provide  a  default value for the internationalization variables that are unset or null. (See the Base Definitions
              volume of IEEE Std 1003.1-2001, Section 8.2, Internationalization Variables for the precedence  of  international-
              ization variables used to determine the values of locale categories.)

       LC_ALL If set to a non-empty string value, override the values of all the other internationalization variables.

       LC_CTYPE
              Determine the locale for the interpretation of sequences of bytes of text data as characters (for example, single-
              byte as opposed to multi-byte characters in arguments).

       LC_MESSAGES
              Determine the locale that should be used to affect the format and contents of diagnostic messages written to stan-
              dard error.

       NLSPATH
              Determine the location of message catalogs for the processing of LC_MESSAGES .


ASYNCHRONOUS EVENTS
       Default.

STDOUT
       The  standard  output  shall  not  be used unless the -j option is specified; in that case, the job identification string
       shall be written to standard output in the following format:


              "%s\n", <jobid>

STDERR
       The standard error shall be used only for diagnostic messages.

OUTPUT FILES
       Output files shall be created or written, or both, according to the contents of command-string.

       If -n is not used, mail files shall be modified following any command or file-access failures on the remote system.

EXTENDED DESCRIPTION
       None.

EXIT STATUS
       The following exit values shall be returned:

        0     Successful completion.

       >0     An error occurred.


CONSEQUENCES OF ERRORS
       Default.

       The following sections are informative.

APPLICATION USAGE
       Note that, for security reasons, many installations limit the list of  commands  executable  on  behalf  of  an  incoming
       request from uux. Many sites permit little more than the receipt of mail via uux.

       Any characters special to the command interpreter should be quoted either by quoting the entire command-string or quoting
       the special characters as individual arguments.

       As noted in uucp, shell pattern matching notation characters appearing in pathnames are expanded on the appropriate local
       system.  This  is  done  under the control of local settings of LC_COLLATE and LC_CTYPE . Thus, care should be taken when
       using bracketed filename patterns, as collation and typing rules may vary from one system to another. Also be aware  that
       certain  types  of  expression  (that is, equivalence classes, character classes, and collating symbols) need not be sup-
       ported on non-internationalized systems.

EXAMPLES
        1. The following command gets file1 from system a and file2 from system b, executes diff on the local system,  and  puts
           the results in file.diff in the local PUBDIR directory. ( PUBDIR is the uucp public directory on the local system.)


           uux "!diff a!/usr/file1 b!/a4/file2 >!~/file.diff"

        2. The  following  command fails because uux places all files copied to a system in the same working directory. Although
           the files xyz are from two different systems, their filenames are the same and conflict.


           uux "!diff a!/usr1/xyz b!/usr2/xyz >!~/xyz.diff"

        3. The following command succeeds (assuming diff is permitted on system a) because the file local to  system  a  is  not
           copied to the working directory, and hence does not conflict with the file from system c.


           uux "a!diff a!/usr/xyz c!/usr/xyz >!~/xyz.diff"

RATIONALE
       None.

FUTURE DIRECTIONS
       None.

SEE ALSO
       Shell Command Language, uucp, uuencode, uustat

COPYRIGHT
       Portions  of  this  text are reprinted and reproduced in electronic form from IEEE Std 1003.1, 2003 Edition, Standard for
       Information Technology -- Portable Operating System Interface (POSIX), The Open Group Base Specifications Issue 6,  Copy-
       right (C) 2001-2003 by the Institute of Electrical and Electronics Engineers, Inc and The Open Group. In the event of any
       discrepancy between this version and the original IEEE and The Open Group Standard, the original IEEE and The Open  Group
       Standard   is   the   referee   document.   The   original   Standard   can   be   obtained  online  at  http://www.open-
       group.org/unix/online.html .



IEEE/The Open Group                                           2003                                                       UUX(1P)