Tribblix: manual page: uux.1c

UUX(1C) Communication Commands UUX(1C)

NAME

uux - UNIX-to-UNIX system command execution

SYNOPSIS

uux [-] [-bcCjnprz] [-a name] [-g grade]
[-s filename] [-x debug_level] command-string

DESCRIPTION

The uux utility will gather zero or more files from various systems,
execute a command on a specified system and then send standard output
to a file on a specified system.

Note: 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 (see mail(1)). (Remote execution
permissions are defined in /etc/uucp/Permissions.)

The command-string is made up of one or more arguments that look like
a shell command line, except that the command and file names may be
prefixed by system-name!. A null system-name is interpreted as the
local system.

File names may be one of the following:

o An absolute path name.

o A path name preceded by ~xxx, where xxx is a login name on
the specified system and is replaced by that user's login
directory.

Anything else is prefixed by the current directory.

As an example, the command:

example% uux "!diff sys1!/home/dan/filename1 \
sys2!/a4/dan/filename2 > !~/dan/filename.diff"

will get the filename1 and filename2 files from the sys1 and sys2
machines, execute a diff(1) command and put the results in
filename.diff in the local PUBDIR/dan/ directory. PUBDIR is a public
directory defined in the uucp source. By default, this directory is
/var/spool/uucppublic.

Any special shell characters (such as < > ; |) should be quoted
either by quoting the entire command-string, or quoting the special
characters as individual arguments. The redirection operators >>,
<<, >|, and >& cannot be used.

uux will attempt to get all appropriate files to the specified system
where they will be processed. For files that are output files, the
file name must be escaped using parentheses. For example, the
command:

example% uux "a!cut -f1 b!/usr/filename > c!/usr/filename"

gets /usr/filename from system b and sends it to system a, performs a
cut command on that file and sends the result of the cut command to
system c.

uux will notify you if the requested command on the remote system was
disallowed. This notification can be turned off by the -n option. The
response comes by remote mail from the remote machine.

OPTIONS

The following options are supported:

-
The standard input to uux is made the standard
input to the command-string.

-a name
Uses name as the user job identification replacing
the initiator user-id. (Notification will be
returned to user-id name.)

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

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

-C
Forces the copy of local files to the spool
directory for transfer.

-g grade
grade can be either a single letter, number, or a
string of alphanumeric characters defining a
service grade. The uuglist(1C) command determines
whether it is appropriate to use the single letter,
number, or a string of alphanumeric characters as a
service grade. The output from the uuglist command
will be a list of service grades that are available
or a message that says to use a single letter or
number as a grade of service.

-j
Outputs the jobid string on the standard output
which is the job identification. This job
identification can be used by uustat(1C) to obtain
the status or terminate a job.

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

-p
Same as -. The standard input to uux is made the
standard input to the command-string.

-r
Does not start the file transfer, but just queues
the job.

-s filename
Reports status of the transfer in filename. This
option is accepted for compatibility, but it is
ignored because it is insecure.

-x debug_level
Produces debugging output on the standard output.
debug_level is a number between 0 and 9. As
debug_level increases to 9, more detailed debugging
information is given.

-z
Sends success notification to the user.

ENVIRONMENT VARIABLES

See environ(7) for descriptions of the following environment
variables that affect the execution of uux: LANG, LC_ALL, LC_CTYPE,
LC_MESSAGES, and NLSPATH.

EXIT STATUS

The following exit values are returned:

0
Successful completion.

>0
An error occurred.

FILES

/etc/uucp/*
other data and programs

/etc/uucp/Permissions
remote execution permissions

/usr/lib/uucp/*
other programs

/var/spool/uucp
spool directories

ATTRIBUTES

NOTES

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:

example% uux "a!diff b!/home/dan/xyz c!/home/dan/xyz > !xyz.diff"

But the command:

example% uux "a!diff a!/home/dan/xyz c!/home/dan/xyz > !xyz.diff"

will work (if diff is a permitted command.)

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.

The following restrictions apply to the shell pipeline processed by
uux:

o In gathering files from different systems, pathname
expansion in not performed by uux. Thus, a request such as

uux "c89 remsys!~/*.c"

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

o 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.

o The use of the shell metacharacter * will probably not do
what you want it to do.

o The shell tokens << and >> are not implemented.

o The redirection operators >>, <<, >|, and >& cannot be
used.

o The reserved word ! cannot be used at the head of the
pipeline to modify the exit status.

o Alias substitution is not performed.

March 28, 1995 UUX(1C)