Execute - Contains instructions for running commands that require the
resources of a remote system
The Execute (X.*) files contain instructions for running uucp commands that
require the resources of a remote system. They are created by the uux com-
mand. The full pathname of a uux command execute file is a form of the
where the SystemName directory is named for the local computer and the
RemoteSystem directory is named for the remote system. The N character
represents the grade of the work, and the xxxx notation is the 4-digit hex-
adecimal transfer-sequence number; for example, X.zeusN2121.
Note that the grade of the work specifies when the file is to be transmit-
ted during a particular connection. The grade notation is a single number
(0 to 9) or letter (A to Z, a to z). Lower sequence characters cause the
file to be transmitted earlier in the connection than do higher sequence
characters. The number 0 (zero) is the highest grade, signifying the earli-
est transmittal; z is the lowest grade, signifying the latest transmittal.
The default grade is N.
Standard Entries in an Execute File
An execute file consists of several lines, each with an identification
character and one or more entries:
Line Format and Description
User Line U UserName SystemName
Specifies the login name of the user issuing the uux
command and the name of the system from which the
command was issued.
Error Status Line N or Z
Indicates the error status.
The N character means that a failure message is not
sent to the user issuing the uux command if the
specified command does not execute successfully on
the remote system.
The Z character means that a failure message is sent
to the user issuing the uux command if the specified
command does not execute successfully on the remote
Requester's Name R UserName
Specifies the login ID of the user requesting the
remote command execution.
Required File Line F FileName
Contains the names of the files required to execute
the specified command on the remote system. The
FileName parameter can be either the complete path-
name of the file, including the unique transmission
name assigned by the uucp program, or simply the
transmission name without any path information.
The Required File Line can contain zero or more
filenames. The uuxqt daemon checks for the
existence of all listed files before running the
Standard Input Line I FileName
Specifies the standard input to be used.
The standard input is either specified by a << (less
than) symbol in the command string, or is inherited
from the standard input of the uux command if that
command was issued with the - (dash) flag. If stan-
dard input is specified, it also is listed in an F
(Required File) line. If standard input is not
specified, the uucp program uses the /dev/null dev-
Standard Output Line O FileName SystemName
Specifies the names of the file and system that are
to receive standard output from the execution of the
command. Standard output is specified by a >>
(greater than) symbol within the command string.
(The >>>> sequence is not valid in uux commands.) As
was the case with standard input, if standard output
is not specified, the uucp program uses the
/dev/null device file.
Command Line C CommandString
This is the command string that the user requests to
be run on the specified system. The uucp program
checks the /usr/lib/uucp/Permissions file on the
designated computer to see whether the login ID can
run the command on that system. All required files
go to the execute file directory, usually
/usr/spool/uucp/.Xqtdir. After execution, the stan-
dard output is sent to the requested location
1. User fong on local system zeus enters the following command:
uux - "diff /u/fong/out hera!/u/fong/out2 >> ~uucp/DF"
This invokes the uux command to run a diff command on the local sys-
tem, comparing file /u/fong/out with file /u/fong/out2, which is
stored on remote system hera. The output of the comparison is placed
in the DF file in the public directory on the local system.
This command produced the /usr/spool/uucp/hera/X.zeusN212F execute
file, which contains the following information:
U fong zeus
# return status on failure
# return address for status or input return
F /usr/spool/uucp/hera/D.herale954fd out2
O ~uucp/DF zeus
C diff /u/fong/out out2
The user line identifies user fong on system zeus. The error status
line indicates that fong will receive a failure status message if the
diff command fails to execute. The requester is fong, and the file
required to execute the command is the following data file:
The output of the command is to be written to the public directory on
system zeus with the filename DF. (Remember that ~uucp is the short-
hand way of specifying the public directory.) The final line is the
command string that user fong entered with the uux command.
2. The following is another example of an execute file:
U uucp hera
# don't return status on failure
# return address for status or input return
C rmail fong
This indicates that user uucp on system hera is sending mail to user
fong, who is also working on system hera.
Describes access permissions for remote systems
Describes accessible remote systems
Contains uucp command, data, and execute files
Contain instructions for transfers
Contains lists of commands that remote systems are permitted to
Contains files that have been transferred
Commands: diff(1), uux(1)