AIX talk Command and talkd Daemon

清疚 2023-10-05 08:48 18阅读 0赞

## talk Command ##

##  ##

**Purpose**

Converse with another user.

**Syntax**

**talk** \{ *User* | *User***@***Host* | *Host***!***User* | *Host***.***User* | *Host***:***User* \} \[ *Tty* \] \[ *Pty* \]

**Description**

The **/usr/bin/talk** command allows two users on the same host or on different hosts to have an interactive conversation. The **talk** command opens both a send window and a receive window on each user's display. Each user is then able to type into the send window while the **talk** command displays what the other user is typing.

To initiate a conversation, a local user executes the **talk** command and specifies a remote user's login ID. The remote user's login ID can contain NLS characters. If the remote user is on a remote host, the name of the host must also be specified in one of the following ways:

*User***@***Host*

*Host***!***User*

*Host***.***User*

*Host***:***User*

When using full domain names, the only valid form for specifying the user and host is *User***@***Host*. For example, michael@host17.dev.ibm.com initiates a conversation with user michael at host host17 in the dev.ibm.com domain.

When the local user initiates the conversation, a message is sent to the remote user, inviting a conversation. If the local user also specifies tty, the invitation message is sent only to the specified terminal. Otherwise, the invitation is sent to the remote user's login terminal. This usually is the console, but it may be another terminal. Once this invitation is received, the **talk** command displays two windows on the local user's terminal and displays progress messages until the remote user responds to the invitation.

**Note:** If the remote user is running AIXwindows and has no other terminals open, the **talk** command cannot send an invitation.

To have the conversation, the remote user also has to execute the **talk** command from any terminal and specify the local user's account name and host name, if appropriate. When the remote user accepts the invitation, the **talk** command displays two windows on each user's terminal. One window displays what is typed by the local user; the other window displays what is typed by the remote user. To end the conversation, either user can press the Interrupt (Ctrl-C) key sequence and the connection is closed. The Interrupt key sequence can be displayed and modified using the **stty** command.

If the users involved in the conversation are using National Language Support (NLS) capabilities, their terminals must support the printing of NLS characters. The same is true for conversations using Kanji capabilities; the terminals being used must support the printing of Kanji characters.

The **talk** command requires a valid address to which to bind. The host name of the remote machine must be bound to a working network interface, which is usable by other network commands, such as the **ping** command. If a machine has no network interface, that is a standalone machine, it must bind its host name to the loopback address (127.0.0.1) in order for the **talk** command to work. For example, two users named local and remote on a standalone machine could initiate a conversation, using the **talk** command, by entering:

talk remote@loopback

To which user remote responds:

talk local@loopback

To disallow **talk** command invitations, the remote user can issue the **mesg** command.

**Note:** The **talk** command uses the Talk 4.3 protocol.

**Security**

**Attention RBAC users and Trusted AIX users**This command can perform privileged operations. Only privileged users can run privileged operations. For more information about authorizations and privileges, see Privileged Command Database in *Security*. For a list of privileges and the authorizations associated with this command, see the **lssecattr** command or the **getcmdattr** subcommand.

**Examples**

1.  To talk to a user logged in on a remote host, enter:

talk dale@host2

In this example, the local user wants to talk with user dale who is logged in on host2.

1.  To talk to a user only if that user is logged in on the console of a remote host, enter:

talk dale@host2 console

User dale receives this message only if logged in on the console at host2.

##  ##

## talkd Daemon ##

**Purpose**

Provides the server function for the **talk** command.

**Syntax**

**/usr/sbin/talkd** \[ [**-s** ][-s_]\]

**Description**

**Note:** The **talkd** daemon is normally started by the **inetd** daemon. It can also be controlled from the command line, using SRC commands.

The **/usr/sbin/talkd** daemon is the server that notifies a user (the recipient) that another user (the caller) wants to initiate a conversation. The daemon sets up the conversation if the recipient accepts the invitation. The caller initiates the conversation by executing the **talk** command specifying the recipient. The recipient accepts the invitation by executing the **talk** command specifying the caller.

The **talkd** daemon listens at the socket defined in the **/etc/services** file. When the **talkd** daemon receives a LOOK\_UP request from a local or remote **talk** process, the **talkd** daemon scans its internal invitation table for an entry that pairs the client process (the local or remote **talk** process) with a caller.

If no entry exists in the invitation table, the **talkd** daemon assumes that the client process is the caller. The **talkd** daemon then receives the client process' ANNOUNCE request. The **talkd** daemon broadcasts an invitation on the remote computer where the recipient first logged in (unless the caller specifies a particular tty device). This terminal usually is the console, but it may be another terminal.

Otherwise, the invitation is sent to the terminal that the second user first logged in to. This usually is the console, but it may be another terminal.

If an entry does exist in the **talkd** daemon's internal invitation table, the **talkd** daemon assumes that the client is the recipient. The **talkd** daemon returns the appropriate rendezvous address to the **talk** process for the recipient. The recipient process then establishes a stream connection with the caller process.

**Note:** The **talkd** daemon uses the Talk 4.3 protocol. The subserver name for the AIX® protocol is **ntalk**.

Changes to the **talkd** daemon can be made using the System Management Interface Tool (SMIT) or System Resource Controller (SRC), by editing the **/etc/inetd.conf** or /**etc**/**services** file. Entering talkd at the command line is not recommended. The **talkd** daemon is started by default when it is uncommented in the **/etc/inetd.conf** file.

The **inetd** daemon get its information from the /**etc**/**inetd.conf** file and the /**etc**/**services** file.

After changing the **/etc/inetd.conf** or /**etc**/**services** file, run the **refresh** **-s inetd** or **kill -1** *InetdPID* command to inform the **inetd** daemon of the changes to its configuration file.

Debugging messages are sent to the **syslogd** daemon.

**Note:** The **talkd** daemon should be controlled using the System Management Interface Tool (SMIT) or by changing the **/etc/inetd.conf** file.

**Manipulating the talkd Daemon with the System Resource Controller**

The **talkd** daemon is a subserver of the **inetd** daemon, which is a subsystem of the System Resource Controller (SRC). The **talkd** daemon is a member of the **tcpip** SRC subsystem group. This daemon is enabled by default in the **/etc/inetd.conf** file and can be manipulated by the following SRC commands:

<table> 
 <thead> 
  <tr> 
   <td style="border-color:#e0e0e0;vertical-align:bottom;"> <p style="margin-left:0cm;"><strong>Item</strong></p> </td> 
   <td style="border-color:#e0e0e0;vertical-align:bottom;"> <p style="margin-left:0cm;"><strong>Description</strong></p> </td> 
  </tr> 
 </thead> 
 <tbody> 
  <tr> 
   <td style="border-color:#e0e0e0;vertical-align:top;"> <p style="margin-left:0cm;"><a href="https://www.ibm.com/support/knowledgecenter/ssw_aix_71/s_commands/startsrc.html?view=kc" rel="nofollow"><strong>startsrc</strong></a></p> </td> 
   <td style="vertical-align:top;"> <p style="margin-left:0cm;">Starts a subsystem, group of subsystems, or a subserver.</p> </td> 
  </tr> 
  <tr> 
   <td style="border-color:#e0e0e0;vertical-align:top;"> <p style="margin-left:0cm;"><a href="https://www.ibm.com/support/knowledgecenter/ssw_aix_71/s_commands/stopsrc.html?view=kc" rel="nofollow"><strong>stopsrc</strong></a></p> </td> 
   <td style="vertical-align:top;"> <p style="margin-left:0cm;">Stops a subsystem, group of subsystems, or a subserver.</p> </td> 
  </tr> 
  <tr> 
   <td style="border-color:#e0e0e0;vertical-align:top;"> <p style="margin-left:0cm;"><a href="https://www.ibm.com/support/knowledgecenter/ssw_aix_71/l_commands/lssrc.html?view=kc" rel="nofollow"><strong>lssrc</strong></a></p> </td> 
   <td style="vertical-align:top;"> <p style="margin-left:0cm;">Gets the status or a subsystem, group or subsystems, or a subserver.</p> </td> 
  </tr> 
 </tbody> 
</table>

**Flags**

**Examples**

1.  To start the **talkd** daemon, enter the following:

startsrc [\-t][-t] ntalk

This command starts the **talkd** subserver.

1.  To stop the **talkd** daemon normally, enter the following:

stopsrc [\-t][-t 1] ntalk

This command allows all pending connections to start and existing connections to complete but prevents new connections from starting.

1.  To force stop the **talkd** daemon and all **talkd** connections, enter the following:

stopsrc [\-f][-f] \-t ntalk

This command terminates all pending connections and existing connections immediately.

1.  To display a short status report about the **talkd** daemon, enter the following:

lssrc [\-t][-t 2] ntalk

This command returns the daemon's name, process ID, and state (active or inactive).

**Files**

[-s_]: https://www.ibm.com/support/knowledgecenter/ssw_aix_71/t_commands/talkd.html?view=kc#talkd__row-d3e74534
[-t]: https://www.ibm.com/support/knowledgecenter/ssw_aix_71/s_commands/startsrc.html?view=kc#startsrc/row-d3e48117
[-t 1]: https://www.ibm.com/support/knowledgecenter/ssw_aix_71/s_commands/stopsrc.html?view=kc#stopsrc/row-d3e51682
[-f]: https://www.ibm.com/support/knowledgecenter/ssw_aix_71/s_commands/stopsrc.html?view=kc#stopsrc/row-d3e51594
[-t 2]: https://www.ibm.com/support/knowledgecenter/ssw_aix_71/l_commands/lssrc.html?view=kc