uux -- UNIX-to-UNIX system command execution


uux [ -bjnrz ] [ -c | -C ] [ -p | - ] [ -a name ] [ -g grade ] [ -s file ]
[ -x debug_level ] command_string


uux gathers zero or more files from various systems, executes a command on a specified system and then sends standard output to a file on a specified system.

The command_string is similar to a shell command line except that the command and any filename arguments are prefixed by a system name and ``!''. This notation indicates the systems that the command is to be run on, and where the files are to be found; a null system name is interpreted as your local system.

Filenames may be one of:

uux attempts to copy all input files to the system executing the command. Beware of filename clashes that might occur if two identically named files are copied from different systems to the same system.

Output filenames must be surrounded by parentheses (see ``Examples'').

You should escape any special shell characters such as ``<'', ``>'', ``;'', and ``|'' by quoting the entire command-string, or quoting the special characters as individual arguments.

uux notifies you by mail from a remote system that disallows a requested command. (Turn off this notification using the -n option.)

uux understands the following options:

-a name
Use name as the user identification instead of the initiator's name. (The user is notified of this.)

Return whatever standard input was provided to the uux command if the exit status is non-zero.

Do not copy local file to the spool directory for transfer to the remote machine (default).

Force the copy of local files to the spool directory for transfer.

-g grade
grade is a single letter/number; lower ASCII sequence characters will cause the job to be transmitted earlier during a particular conversation.

Output the job ID ASCII string on the standard output which is the job identification. This job identification can be used by uustat to obtain the status or terminate a job.

Do not notify the user if the command fails.

The standard input to uux is made the standard input to command_string. The - form of the option is obsolescent.

Do not start the file transfer, just queue the job.

-s file
Report status of the transfer-in file.

-x debug_level
Produce debugging output on the standard output. debug_level is a number between 0 and 9; higher numbers give more detailed information.

Send success notification to the user.


Get the file1 and file2 files from the usg and pwba machines, execute a diff(C) command and put the results in the file file.diff in the local directory /usr/spool/uucppublic/dan (dan's login directory):

uux "!diff usg!/usr/dan/file1 pwba!/a4/dan/file2 > !~/dan/file.diff"

This example gets /usr/file from system b and sends it to system a, performs a cut command on that file and sends the result to system c (note that the output filename is placed in parentheses):

uux a!cut -f 1 b!/usr/file \(c!/usr/file\)


Only the first command of a shell pipeline may have a system-name. All other commands are executed on the system of the first command. The use of the shell metacharacter ``*'' will probably not do what you want it to do. The shell tokens ``<<'' and ``>>'' are not implemented.

The execution of commands on remote systems takes place in an execution directory known to the uucp system. All files required for the execution will be put into this directory unless they already reside on that machine. Therefore, the simple file name (without path or machine reference) must be unique within the uux request. The following command will NOT work:

uux "a!diff b!/usr/dan/xyz c!/usr/dan/xyz > !xyz.diff"

However, the following command will work (if diff is a permitted command):

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


For security reasons, most installations limit the list of commands executable on behalf of an incoming request from uux, permitting only the receipt of mail(C). (Remote execution permissions are defined in /usr/lib/uucp/Permissions.)

Protected files and files that are in protected directories that are owned by the requester can be sent in commands using uux. However, if the requester is root, and the directory is not searchable by ``other'', the request will fail.


spool directories

remote execution permissions

other data and programs

See also

mail(C), uucp(C), uustat(C)

Standards conformance

uux is conformant with:

ISO/IEC DIS 9945-2:1992, Information technology - Portable Operating System Interface (POSIX) - Part 2: Shell and Utilities (IEEE Std 1003.2-1992);
AT&T SVID Issue 2;
X/Open CAE Specification, Commands and Utilities, Issue 4, 1992.

© 2003 Caldera International, Inc. All rights reserved.
SCO OpenServer Release 5.0.7 -- 11 February 2003