14    The UUCP Networking Commands

This chapter describes the UNIX-to-UNIX Copy Program (UUCP). Using UUCP enables you to:

• Perform tasks on a remote host

• Transfer files between a local and remote host

• Work in background mode

• Switch back and forth between the local and remote host, performing tasks on either or both, concurrently

For an overview of UUCP system management and tasks, see the Network and Communications Overview.

With UUCP, you can connect over a hardwired asynchronous line, a network, or a telephone line (using modems at both ends) to:

• Another workstation

• Another computer running a UNIX based operating system

• A computer running an operating system that is not UNIX based (this requires certain hardware and software)

14.1    UUCP Pathname Conventions

UUCP pathnames follow the same conventions as the operating system with the following exceptions:

• Relative pathnames may not work with all UUCP commands. If not, reenter the command and use the full pathname.

• On hosts that support UUCP, the /usr/spool/uucppublic directory is set up for transferring data among other hosts. The brief form of this directory is ~uucp.

• The pathname for a file on a remote host requires an exclamation point, (!) after the host name. For example, sea!/research/new specifies the file new in the directory /research on host sea.

• Sometimes to specify a file, you must provide the names of the remote hosts along the network path. To do so in the Bourne or Korn shells, put an exclamation point (!) after each host name. For example, gem!car!sea!/research/cells specifies the file cells in directory /research on host sea, which is reachable through host car; car is reachable through host gem. In the C shell, the exclamation point (!) will be mistranslated unless you precede it with a backslash (\), for example:
  gem\!car\!sea\!/research/cells
  

14.2    Finding Hosts that Support UUCP

To communicate with a remote host by using UUCP commands from your local host, you must determine which other hosts support the UUCP protocol. The UUCP uuname utility displays a list of all hosts with which you can communicate using UUCP from your local host. The following example shows the uuname command with output.

%  uuname

elvis
fab4

This example shows that two remote hosts are accessible to the local host through UUCP. To identify the local host, use the -l option to the uuname command. For example:

%  uuname -l

music

By using UUCP commands among compatible hosts, a user on host music can send to or receive files from hosts elvis or fab4.

For more information, refer to the uuname(1) reference page.

14.3    Connecting to a Remote Host

Before you can use UUCP commands, you must connect your local host to the remote host. There are three commands you can use to connect to a remote host:

• The cu and tip commands establish a full-duplex connection, giving the appearance of being directly logged in to the remote host. This connection enables the simultaneous transfer of data between the hosts.

• The ct command establishes a remote connection by letting you dial an attached terminal and log in via a modem and telephone line.

Note

A remote connection is subject to the security features on the local and remote host. See your system administrator for more information.

14.3.1    Using cu to Connect to a Remote Host

The cu command and its options enable you to connect to a remote host, log in to it, and perform tasks there from your local host. You can perform tasks on each host by switching back and forth between the two. If both hosts use the operating system, you can enter commands on the remote host from your local host.

14.3.1.1    Using cu to Connect by Name to a Remote Host

The following steps show how to use the cu command to connect from local host earth to remote host moon, log in to moon, and enter a command there:

1. Enter the following cu command at the local system prompt; a message verifies the connection:

   earth%  cu moon
   

   Connected
   

   The login prompt for the remote host will be displayed. When connecting to some remote hosts, you may need to press the Return key several times before a login prompt is displayed.

2. Log in to host moon at the login prompt. The system prompt for host moon is displayed.

3. At the system prompt, enter any command that host moon supports. For example, to list the contents of the /usr/geog/crater/earthside directory, enter the following command at the system prompt:

   moon%  ls /usr/geog/crater/earthside
   

   copernicus.dat
   tycho.dat
   

   moon% 
   

Note

The preceding example may not work for all cu connections. It is used here as a brief, general example. See your system administrator for more information.

After logging in to the remote host, you can switch back and forth between it and the local host because they run concurrently. To return to your local host and enter a command there, type a tilde and an exclamation point (~!) followed directly by the command, or wait for the local host prompt to display and then enter the command. To return to the remote host, press Ctrl/d.

14.3.1.2    Using cu to Specify a Directly-Connected Remote Host

To connect to a directly-connected remote host, use the cu command with the -l option to name the hardwired line that connects the two computers. Most of these communication lines have names that are variations of the standard device name, tty.

To use the cu command with the -l option to connect to a remote host with an unknown name, but which uses hardwired device ttyd0, enter the following command:

earth%  cu -lttyd0

Connected

After the connection is made, you can log in to and execute commands on remote host moon. Refer to the steps in Section 14.3.1.1.

To return to the local host, type a tilde and an exclamation point (~!) followed directly by the command or wait for the local system prompt to display before entering the command. To return to the remote host, press Ctrl/d.

Note

If you use the -l option, but still enter the name of a remote host, no error message will be generated. Instead, cu will try to connect to the first available line for the requested host name, ignoring the specified line. If it makes the connection, it may not be the one you intend.

14.3.1.3    Using cu to Connect by Telephone to a Remote Host

You can use cu to connect by telephone to a remote host whenever the remote host has not been set up to communicate with the local host through UUCP. To do so, the following conditions must be met:

• Both the local and the remote host are connected to modems.

• You know the telephone number of the remote modem and have a valid login on that host.

The following example shows how to use the cu command to connect to a remote host that has a long-distance telephone number of 1-612-555-6789. The -s option specifies a transmission rate of 300 baud. Assuming that dialing 9 is necessary for an outside dial tone, enter the following cu command at the local system prompt:

earth%  cu -s300 9=16125556789

Connected

After the connection is made, you can log in to and execute commands on the remote host. (Refer to the steps in Section 14.3.1.1).

To return to the local host, type a tilde and an exclamation point (~!) followed directly by the command or wait for the local system prompt to display before entering the command. To return to the remote host, press Ctrl/d.

If you do not use the -s option to specify a transmission speed, an appropriate rate is selected by default from data in /usr/lib/uucp/Devices.

For added security use the -n option, which prompts you for the telephone number. This suppresses the display of the phone number with the ps command, which would otherwise display the number with the cu command that you enter.

Table 14-1 summarizes the cu command options and entries. See the cu(1) reference page for more information.

Table 14-1: Options to the cu Command

14.3.1.4    Local cu Commands

While connected by cu to a remote host, you can use local cu commands to perform the following tasks:

• Go back and forth between the local and remote hosts

• Change directories on the local host

• Copy files between local and remote hosts

• Terminate a remote connection

To return temporarily to the local host to work, type a tilde and an exclamation point (~!) at the remote system prompt; wait for the local system prompt to be displayed in the following form, where local is the name of the local host:

~ [ local ] !

Instead of waiting for the local system prompt to display, you can enter the command immediately after typing the ~! that accesses the local host. For example, while connected by cu to remote host moon, you can enter the following command to return to local host earth and use the cat command to read the /usr/crew/r2/asimov/AI file:

moon%  ~!cat /usr/crew/r2/asimov/AI

There are three cu local commands for tasks that are performed very often. You enter these commands from the remote host to perform tasks on the local host while you continue working on the remote host. These commands are preceded by a tilde and a percent symbol:

~%cd directory_name	changes the directory on the local host
~%take from [to]	copies a file from the remote host to the local host
~%put to [from]	copies a file from the local host to the remote host

For example, while connected by cu to remote host moon, you can change the current directory on local host earth from /usr/geog/ocean to /usr/geog/ocean/pacific by entering the following command:

moon%  ~%cd pacific

While connected by cu to remote host moon, you can copy the file, /usr/ETI/clavius to the file /usr/NASA/decode on local host earth by entering the ~%take local command at the remote system prompt:

moon%  ~%take /usr/ETI/clavius /usr/NASA/decode

While connected by cu to remote host moon, you can copy the local file /usr/NASA/jupiter to the file, /usr/ETI/clavius/hal9 on the remote host by entering the ~%put local command at the remote system prompt:

moon%  ~%put /usr/NASA/jupiter /usr/ETI/clavius/hal9

Note

Before using the ~%take and ~%put commands, verify that the destination directory exists. Unlike the uucp command, these cu local commands do not create intermediate directories during file transfers.

You can transfer only ASCII files with ~%take and ~%put. (For example, a PostScript file is an ASCII file, but a DECwrite file is not.)

14.3.1.5    Using cu to Connect a Local Computer to Several Remote Computers

You can enter the cu to connect host X to host Y, log on to host Y, and then enter the cu command there to connect to host Z. You then have one local host computer, X, and two remote host computers, Y and Z.

You can run an operating system command on host Z after you log in there. Then, from Z, you can run commands on the other hosts as follows:

• To run a command on host X, prefix the command with a single tilde (~)

• To run a command on host Y, prefix the command with two tildes (~~)

Table 14-2 summarizes the most common cu local commands. For information about other cu local commands, refer to cu(1).

Table 14-2: Local cu Commands

14.3.2    Using tip to Connect to a Remote Host

The tip command and its options enable you to connect to a remote host, log in to it, and perform tasks there from your local host. You can do tasks on each by switching back and forth between the two. If both hosts use the operating system, you can enter commands on the remote host from your local host.

14.3.2.1    Using tip to Connect by Name to a Remote Host

The following steps show how to use the tip command to connect from local host earth to remote host moon, log in to moon, and enter a command there:

1. Enter the following tip command at the local system prompt; a message verifies the connection:

   earth%  tip moon
   

   Connected
   

   The login prompt for the remote host will be displayed. When connecting to some remote hosts, you may need to press the Return key several times before a login prompt is displayed.

2. Log in to host moon at the login prompt. The system prompt for host moon is displayed.

3. At the system prompt, enter any command that host moon supports. For example, to list the contents of the /usr/geog/crater/darkside directory, enter the following command at the system prompt:

   moon%  ls /usr/geog/crater/darkside
   

   copernicus.dat
   tycho.dat
   

   moon% 
   

Note

The preceding example may not work for all tip connections. It is used here as a brief, general example. See your system administrator if necessary.

After logging in to the remote host, you can switch back and forth between it and the local host because they run concurrently. To return to your local host and enter a command there, type a tilde and an exclamation point (~!) followed directly by the command, or wait for the local host prompt to display and then enter the command. To return to the remote host, press Ctrl/d.

14.3.2.2    Using tip to Connect by Telephone to a Remote Host

You can use the tip command to connect by telephone to a remote host if the following conditions are met:

• Both the local and the remote host are connected to modems.

• You know the telephone number of the remote modem or there is an entry for the remote host in /etc/remote.

The following steps show how to use the tip command to connect to a remote host that has the local telephone number 555-1234 and specifies a transmission rate of 300 baud:

1. Enter the following tip command at the local prompt, jupiter; a message verifies the connection:

   jupiter%  tip -300 5551234
   

   Connected
   

2. Press the Return key. When connecting to some remote hosts, you may need to press the Return key several times before the remote host's login prompt is displayed.

3. Log in at the remote host login prompt. The connection to your local host is still open, so you can work on the local or remote host.

Note

If you do not specify a transmission speed, the tip command uses a 1200-baud rate by default. When transferring a large file, you may want to specify the low 300-baud rate for less interference on the line.

The following steps show how to use the tip command to connect, with a 300-baud transmission rate, to a remote host that has a long-distance telephone number of 1-612-555-9876.

1. Assuming that you must dial 9 for an outside dial tone, enter the following tip command at the prompt of local host earth; a message verifies the connection:

   earth%  tip -300 9,16125559876
   

   Connected
   

2. Press the Return key. When connecting to some remote hosts, you may need to press the Return key several times before the remote host's login prompt is displayed.

3. Log in at the remote host's login prompt. The connection to your local host is still open, so you can work on the local or remote host.

For information about customizing the /etc/remote and /etc/phones files, refer to the book, Network Administration and the remote(4) and phones(4) reference pages.

Table 14-3 summarizes the tip command options and entries. See the tip(1) reference page for more information.

Table 14-3: Options to the tip Command

14.3.2.3    Local tip Commands

While connected by tip to a remote host, you can use local commands to perform the following tasks:

• Go back and forth between the local and the remote host

• Change directory on the local host from the remote host

• Copy files between local and remote hosts

• Terminate a remote connection

To return temporarily to the local host and enter commands there, type a tilde and exclamation point (~!) at the remote system prompt. The local system prompt will display in the following form, where shell is the name of the local shell and pmt is the prompt for the local shell, either % for the C shell or $ for the Bourne or Korn shell:

~ [ shell ] pmt !

To return to the remote host, press Ctrl/d at the local system prompt. To terminate the tip process, type a tilde and press Ctrl/d (~^D).

You can use the following tip commands from the remote host to perform tasks on the local host while you continue working on the remote host. These commands are preceded by a tilde:

~c directory_name	change the local directory
~t from [to]	copy a file from the remote host to a file on the local host
~<	copy a file from the remote host to a file on the local host
~p from [to]	copy a file from the local host to a file on the remote host
~>	copy a file from the local host to a file on the remote host

For example, while connected by tip to remote host moon, you can change the current directory on local host earth, from /usr/geog/polar to /usr/geog/polar/arctic by entering the following command:

moon%  ~c arctic

While connected by tip to remote host moon, you can copy the /usr/darkside/temp/dat file to the /usr/NASA/bios/temp file on local host earth by entering the following command:

moon%  ~t /usr/darkside/temp/dat /usr/NASA/bios/temp

While connected by tip to remote host moon, you can copy the local /usr/NASA/bios/warn file to the /usr/darkside/temp/change file on the remote host by entering the following command:

moon%  ~p /usr/NASA/bios/warn /usr/darkside/temp/change

Note

You can only transfer ASCII files with the ~t and ~p commands. (For example, a PostScript file is an ASCII file, but a DECwrite file is not.)

Neither ~t nor ~p checks for file transfer errors; the uucp command provides this verification.

14.3.2.4    Using tip to Connect a Local Computer to Several Remote Computers

You can enter the tip command to connect host X to host Y, log on to host Y, and then enter the tip command there (if Y supports tip) to connect to host Z. You then have one local host computer, X, and two remote host computers, Y and Z.

You can run an operating system command on host Z (if Z is a Digital UNIX host) after you log in there. Then, from Z, you can run commands on the other hosts as follows:

• To run a command on host X, prefix the command with a single tilde (~)

• To run a command on host Y, prefix the command with two tildes (~~)

Note

A command sequence that begins with a tilde (~) can be interpreted by tip only if it is at the beginning of the command line.

Table 14-4 summarizes the most common tip local commands. For information about other tip local commands, refer to tip(1).

Table 14-4: Local tip Commands

Note

The tip program uses system prompts and character sequences that match a system's interrupt sequence to signal the end of file transfers through the ~< or ~> command. These values are configured in the /etc/remote file. See the remote(4) reference page for more information.

14.3.3    Using ct to Connect to a Remote Terminal with a Modem

The ct command enables a user on a remote ASCII terminal with a modem to communicate with a local host with a modem over a telephone line. The remote terminal user can then log in and work on the local host. If there are no available telephone lines, the ct command displays a message and asks if you want to wait for one.

The ct command is useful in the following situations:

• When secure communications are necessary:

  Because the local host contacts the remote terminal, the remote user does not need to know the telephone number of the local host. The local user entering ct can monitor the work of the remote user.

• When the cost for the telephone connection should be charged either to the local site or to a specific account on the remote terminal (like a collect call). The -h option can be omitted to emulate making a collect call. The user on a remote terminal enters the ct command without the -h option.

The following ct features are useful under certain circumstances:

• You can instruct ct to continue dialing a number until the connection is established or until a set length of time has elapsed.

• You can specify more than one telephone number, and ct can dial each modem until a connection is established.

Note

Usually, a user on the remote terminal calls the user on the local host to request a ct session. If such connections occur often, your system manager may want to set up UUCP so that a local host automatically enters ct to one or more specified terminals at a designated time. For information about customizing UUCP, see your system administrator.

For example, to connect to a remote terminal modem at the same site as yours, enter the following command. The remote modem has a telephone number of 7-6092:

earth%  ct 76092

Allocated dialer at 1200 baud
Confirm hang_up? (y to hang_up)

After entering the command, a message verifies the connection and prompts you to either hang up any other phone lines currently in use or cancel the command. The following example shows how to use the ct command to connect to a remote terminal modem with a local telephone number of 555-0043, specifying 9 for an outside line and the -w option for a 2-minute wait for the modem line:

earth%  ct -w2 9=5550043

Allocated dialer at 1200 baud
Confirm hang_up? (y to hang_up)

As before, you are prompted to either hang up any other phone lines currently in use or cancel the command.

The following example shows how to use the ct command to connect from local host earth, to a remote terminal modem with a long-distance number of 1-201-555-7824, specifying 9 for an outside line and the -w option for a 5-minute wait for the modem line:

earth%  ct -w5 9=12015557824

Allocated dialer at 1200 baud
Confirm hang_up? (y to hang_up)

You are prompted to either hang up any other phone lines currently in use or cancel the command.

See the ct(1) reference page for more information.

Table 14-5 summarizes ct command options and required entries.

Table 14-5: Options to the ct Command

14.4    Using uux to Run Commands on Remote Hosts

The uux command enables you to run commands on a remote host while you work on your local host. If the command does not exist on the remote host, uux does not execute, and the remote host will notify you by mail. If the command executes and produces output (for example, cat or diff), you can specify that uux place that output in a file on any specified host.

Note

For security reasons, certain sites may restrict the use of some commands through uux. Also, enhanced security features on the local host may affect whether certain commands can be run on remote hosts through uux. See your system administrator for more information.

The uux command syntax depends on how the command interpreter of a given shell treats special characters. The syntax is the same for the Bourne and Korn shells, but different for the C shell.

Regardless of the shell from which you use uux, there are two ways to specify the destination:

uux [ option... ] " commandstring > destination "

uux [ option... ] commandstring \ { destination \ }

In the first syntax statement, the right-angle bracket (the redirection symbol) (>) directs the output of the remote command to a destination directory or file. A pair of double quotation marks (" ") encloses the entire command because the redirection symbol, the right-angle bracket (>), is a special character. Whenever you use any of the following characters in a command line, you must enclose that character or the entire command in double quotation (" ") marks:

• left-angle bracket (<)

• right-angle bracket (>)

• semi-colon (;)

• vertical bar or pipe (|)

• plus sign (+)

• left-bracket ([)

• right-bracket (])

• question-mark (?)

In the second syntax statement, enclose the destination name within braces ({ }). You must type a backslash (\) before each brace because braces are special characters to the shell command interpreter. Without backslashes, the braces would be misinterpreted.

When specifying the pathname of a destination file, you can use a full name, or a pathname preceded by ~user/ where user is the name of the user's login directory.

Output files must be writable. If you are uncertain about the permission status of a specific target output file, direct the results of the command to the /usr/spool/uucppublic directory; ~uucp is a brief way of specifying this directory from a shell.

14.4.1    Using uux from the Bourne or Korn Shells

from system moe: file junk
?

jobid date/time status system_name username size file

sunC3113  Thu Jun 04 17:47:25 1996 S sun doc 289  D.car471afd8
gemN3130  Thu Jun 04 09:14:30 1996 R gem geo 338  D.car471bc0a
seaC3120  Wed Jun 03 16:02:33 1996 S sea doc 828  /u/doc/tt
seaC3119  Wed Jun 03 12:32:01 1996 S sea msg rmail doc

skyNlbd7  Wed Jun 03 12:09:30 1996  S  sky  doc  522    /user/doc/A
skyClbd8  Wed Jun 03 12:10:15 1996  S  sky  doc  59     D.3b2a12ce4924
skyC3119  Wed Jun 03 12:11:18 1996  S  sky  doc  rmail  msg

sea  3C      Mon Jul 13 09:14:35 1996  NO DEVICES AVAILABLE
sun  2C      Mon Jul 13 10:02:22 1996  SUCCESSFUL
gem  1C (2)  Mon Jul 13 10:12:48 1996  CAN'T ACCESS DEVICE