uux - Remote command execution over UUCP


uux [ options ] command


The uux command is used to execute a command on a remote system, or to execute a command on the local system using files from remote systems. The command is not executed immediately; the request is queued until the uucico (8) daemon calls the system and executes it. The daemon is started automatically unless one of the -r or --nouucico options is given.

The actual command execution is done by the uuxqt (8) daemon.

File arguments can be gathered from remote systems to the execution system, as can standard input. Standard output may be directed to a file on a remote system.

The command name may be preceded by a system name followed by an exclamation point if it is to be executed on a remote system. An empty system name is taken as the local system.

Each argument that contains an exclamation point is treated as naming a file. The system which the file is on is before the exclamation point, and the pathname on that system follows it. An empty system name is taken as the local system; this must be used to transfer a file to a command being executed on a remote system. If the path is not absolute, it will be appended to the current working directory on the local system; the result may not be meaningful on the remote system. A pathname may begin with ~/, in which case it is relative to the UUCP public directory (usually /usr/spool/uucppublic or /var/spool/uucppublic) on the appropriate system. A pathname may begin with ~name/, in which case it is relative to the home directory of the named user on the appropriate system.

Standard input and output may be redirected as usual; the pathnames used may contain exclamation points to indicate that they are on remote systems. Note that the redirection characters must be quoted so that they are passed to uux rather than interpreted by the shell. Append redirection (>>) does not work.

All specified files are gathered together into a single directory before execution of the command begins. This means that each file must have a distinct base name. For example,

uux ’sys1!diff sys2!~user1/foo sys3!~user2/foo >!foo.diff’

will fail because both files will be copied to sys1 and stored under the name foo.

Arguments may be quoted by parentheses to avoid interpretation of exclamation points. This is useful when executing the uucp command on a remote system.

A request to execute an empty command (e.g., uux sys!) will create a poll file for the specified system.

The exit status of uux is one of the codes found in the header file sysexits.h. In particular, EX_OK ( 0 ) indicates success, and EX_TEMPFAIL ( 75 ) indicates a temporary failure.


The following options may be given to uux.
-, -p, --stdin

Read standard input and use it as the standard input for the command to be executed.

-c, --nocopy

Do not copy local files to the spool directory. This is the default. If they are removed before being processed by the uucico (8) daemon, the copy will fail. The files must be readable by the uucico (8) daemon, as well as the by the invoker of uux.

-C, --copy

Copy local files to the spool directory.

-l, --link

Link local files into the spool directory. If a file can not be linked because it is on a different device, it will be copied unless one of the -c or --nocopy options also appears (in other words, use of --link switches the default from --nocopy to --copy). If the files are changed before being processed by the uucico (8) daemon, the changed versions will be used. The files must be readable by the uucico (8) daemon, as well as by the invoker of uux.

-g grade, --grade grade

Set the grade of the file transfer command. Jobs of a higher grade are executed first. Grades run 0 ... 9 A ... Z a ... z from high to low.

-n, --notification=no

Do not send mail about the status of the job, even if it fails.

-z, --notification=error

Send mail about the status of the job if an error occurs. For many uuxqt daemons, including the Taylor UUCP uuxqt, this is the default action; for those, --notification=error will have no effect. However, some uuxqt daemons will send mail if the job succeeds unless the --notification=error option is used, and some other uuxqt daemons will not send mail if the job fails unless the --notification=error option is used.

-r, --nouucico

Do not start the uucico (8) daemon immediately; merely queue up the execution request for later processing.

-j, --jobid

Print jobids on standard output. A jobid will be generated for each file copy operation required to perform the operation. These file copies may be cancelled by passing the jobid to the --kill switch of uustat (1), which will make the execution impossible to complete.

-a address, --requestor address

Report job status to the specified e-mail address.

-x type, --debug type

Turn on particular debugging types. The following types are recognized: abnormal, chat, handshake, uucp-proto, proto, port, config, spooldir, execute, incoming, outgoing. Only abnormal, config, spooldir and execute are meaningful for uux.

Multiple types may be given, separated by commas, and the --debug option may appear multiple times. A number may also be given, which will turn on that many types from the foregoing list; for example, --debug 2 is equivalent to --debug abnormal,chat.

-I file, --config file

Set configuration file to use. This option may not be available, depending upon how uux was compiled.

-v, --version

Report version information and exit.


Print a help message and exit.


uux -z - sys1!rmail user1
Execute the command ’’rmail user1’’ on the system sys1, giving it as standard input whatever is given to uux as standard input. If a failure occurs, send a message using mail (1).

uux ’diff -c sys1!~user1/file1 sys2!~user2/file2 >!file.diff’
Fetch the two named files from system sys1 and system sys2 and execute diff putting the result in file.diff in the current directory. The current directory must be writable by the uuxqt (8) daemon for this to work.

uux ’sys1!uucp ~user1/file1 (sys2!~user2/file2)’
Execute uucp on the system sys1 copying file1 (on system sys1) to sys2. This illustrates the use of parentheses for quoting.


The remote system may not permit you to execute certain commands. Many remote systems only permit the execution of rmail and rnews.

Some of the options are dependent on the capabilities of the uuxqt (8) daemon on the remote system.


mail(1), uustat(1), uucp(1), uucico(8), uuxqt(8)


Files can not be referenced across multiple systems.

Too many jobids are output by --jobid, and there is no good way to cancel a local execution requiring remote files.


Ian Lance Taylor (ian [AT]