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AIX Version 4.3 Commands Reference, Volume 5

uucico Daemon


Transfers Basic Networking Utilities (BNU) command, data, and execute files to remote systems.


uucico-r RoleNumber ] [ -x DebugLevel ] -s SystemName


The uucico daemon transfers Basic Networking Utilities (BNU) command (C.*), data (D.*), and execute (E.*) files, created by the uucp and uux commands, to a specified remote system. Both the local and remote systems run the uucico daemon, and the two daemons communicate with each other to complete transfer requests.

The uucico daemon performs the following actions:

  1. Scans the spooling directory (/var/spool/uucp/SystemName) on the local system for transfer requests.
  2. Selects the device used for the communications connection after checking the /etc/uucp/Devices file and the lock files in the /etc/locks directory.
  3. Places a call to the specified remote system using information in the Systems, Dialers, and Dialcodes files located in the /etc/uucp directory.
  4. Performs the required login sequence specified in the Systems file.
  5. Checks permissions listed in the /etc/uucp/Permissions file.
  6. Checks scheduling limits in the Maxuuscheds and Maxuuxqts files located in the /etc/uucp directory.
  7. Runs all transfer requests from both the local and the remote system, placing the transferred files in the public directories (/var/spool/uucppublic/*).
  8. Logs transfer requests and completions in files in the /var/spool/uucp/.Log/uucico directory.
  9. Notifies specified users of transfer requests.

Usually the uucico daemon is called by the uucp and uux commands when needed and is started periodically by the BNU scheduling daemon, uusched, which is started by the cron daemon.

The uucico daemon can be started from the command line for debugging. The BNU uutry, Uutry, and uukick commands also start the uucico daemon with debugging turned on.

  1. Either you must be in the /usr/sbin/uucp directory when you call the uucico daemon, or you must call the daemon with the full path name, /usr/sbin/uucp/uucico.
  2. In the case of a uux command request for the execution of a command on a remote system, the uucico daemon transfers the files and the uuxqt daemon executes the command on the remote system.


-r RoleNumber Specifies the server and client relationship. The role numbers are 1 for server mode and 0 for client mode. If the -r flag is not used, the uucico daemon is started in client mode (-r 0), because the uucico daemon is generally started automatically by a BNU command or daemon. When the uucico daemon is started manually, this flag should be set to 1.
-x DebugLevel Displays debugging information on the screen of the local terminal. The valid range for the DebugLevel variable is 0 to 9, with a default of 5. Higher numbers cause the information to be more detailed. This flag is useful for diagnosing problems with the expect-send sequence in the /etc/uucp/Systems file.
-s SystemName Specifies the name of the remote system. This flag is required when starting the uucico daemon from the command line. The SystemName variable is supplied internally when the uucico daemon is started automatically.
Note: System names must contain only ASCII characters.


To call the uucico daemon from the command line, enter:

/usr/sbin/uucp/uucico -r -s hera &

to start the daemon as a background process and contact remote system hera .


/etc/locks /*
                          Contains lock files which prevent multiple uses of devices and multiple calls to systems.
/usr/sbin/uucp/* Contains the uucico daemon and the configuration files for BNU.
                          Contains information about available devices.
                          Contains dialing code abbreviations.
                          Specifies initial handshaking on a connection.
                          Limits scheduled jobs.
                          Limits remote command executions.
                          Describes access permissions for remote systems.
                          Describes accessible remote systems.
                          Lists uucico daemon errors that BNU cannot correct.
/var/spool/uucp/.Log/uucico /*
                          Contains uucico daemon log files.
                          Lists the last time a remote system was contacted and the minimum time until the next retry.
/var/spool/uucp/SystemName /*
                          Contains C.*, D.*, and X.* files to be transferred by the uucico daemon.
                          Contains command files.
                          Contains data files.
                          Contains execute files.
                          Contain files after transfer by the uucico daemon.

Related Information

The cron daemon, uusched daemon.

The uucp command, uukick command, uuq command, uustat command, uusnap command, uutry command, Uutry command, uux command.

How to Monitor a BNU Remote Connection, How to Monitor a BNU File Transfer, How to Use the uucico Daemon to Debug BNU Login Failures in AIX Version 4.3 System Management Guide: Communications and Networks.

Understanding the BNU Daemons, Understanding the BNU File and Directory Structure in AIX Version 4.3 System Management Guide: Communications and Networks.

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