{"id":242,"date":"2020-08-18T19:23:47","date_gmt":"2020-08-18T20:23:47","guid":{"rendered":"http:\/\/www.linux-tutorial.info\/?page_id=77"},"modified":"2020-08-22T19:26:40","modified_gmt":"2020-08-22T20:26:40","slug":"this-is-the-page-title-toplevel-77","status":"publish","type":"page","link":"http:\/\/www.linux-tutorial.info\/?page_id=242","title":{"rendered":"User Communication"},"content":{"rendered":"\nUser Communication<\/title>\n<question id=\"151\" text=\"Which of the following is not a communication tool?\" \/>\n<p>If you are running a multiuser system like Linux, you\nshould expect to find other users on your system. (I guess that’s why it is a\nmulti-user system.) Although there are many built-in mechanisms to keep users\nseparated, sometimes you will want to communicate with other users.\n<\/p>\n<p>\nLinux provides\nseveral tools to do this, depending on exactly what you want to accomplish. If\nyou simply want to send a quick message to someone, for example, to remind him\nor her of a meeting, you might use the write program, which sends (writes) a\nmessage to his or her <glossary>terminal<\/glossary>.\n<\/p>\n<p>\nIn contrast to some other systems (say,\nthe winpop mechanism under Windows), each line is sent when you press Enter. If\nyou are on the receiving end of the message, the system lets you know who sent\nyou the message.\n<\/p>\n<concept id=\"\" description=\"When using the write command you need to specify the terminal if the person you are trying to contact is logged in more than once.\" \/>\n<question id=\"\" type=\"tf\" text=\"The write command will send the message to all terminals on which the specified user is logged in.\" \/>\n<p>\nIf the person you are trying to contact is logged in\nmore than once, you need to specify the <glossary>terminal<\/glossary>\nto which you want to send the message. So, if I wanted to talk to the user jimmo on\n <glossary>terminal<\/glossary> tty6, the command would look like this:<\/p>\n<p>\n<commandexample command=\"write\">write jimmo tty6<\/commandexample>\n<\/p>\n<p>\nIf you omit the <glossary>terminal<\/glossary>,\n<command>write<\/command> is kind enough to let you select which <glossary>terminal<\/glossary>\nto which you want to send the message.\n<\/p>\n<p>\nIt might happen that someone tries the above command and receives the following message:<\/p>\n<p>\n<screenoutput>write: jimmo has messages disabled.<\/screenoutput>\n<\/p>\n<question id=\"153\" text=\"What command would you use to disable sending messages to you (i.e. using write)?\" \/>\n<p>\nThis message means that jimmo has used the <command>mesg<\/command> command to turn\noff such messages. The syntax for this command is<\/p>\n<p>\n<commandexample command=\"mesg\">mesg n<\/commandexample>\n<\/p>\n<p>\nto turn it off and\n<\/p>\n<p>\n<commandexample command=\"mesg\">mesg y<\/commandexample>\n<\/p>\n<p>\nto turn it on. Unless the system <glossary>administrator<\/glossary>\nhas decided otherwise, the command is on by default. I have worked on some systems\nin which the <glossary>administrator<\/glossary>\nchanged the default to off.\n<\/p>\n<question id=\"152\" text=\"When using the wall command, the root user can still send to users who have messaging disabled.\" \/>\n<concept id=\"133\" description=\" When using the wall command, the root user can still send to users who have messaging disabled.\" \/>\n<concept id=\"\" description=\"The wall command sends a message to all logged-in users.\" \/>\n<question id=\"\" type=\"mc\" text=\"What command is used to send messages to all logged-in users?\" \/>\n<p>\nAn extension of <command>write<\/command> is the <command>wall<\/command> command. Instead of simply writing the message to a single user, wall writes as if it were writing on a (where else) wall. That\nis, everyone can see the message when it is written on a wall, and so can every\nuser. The wall command is often used by root to send messages about system status (e.g. when\nthe system is about to be shutdown. Even if a user has disabled messages, the root user can\nstill send them messages using wall.<\/p>\n<question id=\"\" type=\"mc\" text=\"What command\/tool could you use to communicate interactively with another user?\" \/>\n<p>\nIf you want to\nhave an interactive session, you could send write messages back and forth. On\nthe other hand, you could use the <command>talk<\/command> program that was designed to do just\nthat. When talk first connects to the other user, that other user sees on his or\nher screen\n<\/p>\n<p>\n<screenoutput>\nMessage from TalkDaemon@source_machine…\ntalk: connection requested by callers_name@his_machine\ntalk: respond with: talk callers_name@his_machine\n<\/screenoutput><\/p>\n<p>\nAs the message indicates, to respond, you would enter\n<\/p>\n<p>\n<commandexample command=\"talk\">talk callers_name@his_machine<\/commandexample>\n<\/p>\n<p>\nYou might have noticed that you\ncan use <command>talk<\/command> to communicate with users on other machines. If you omitted the\nmachine name, talk would try to contact the user on the local machine\n(localhost). The preceding message would simply say\n<\/p>\n<p>\n<screenoutput>\ntalk: connection requested by callers_name@localhost\n<\/screenoutput><\/p>\n<p>\nYou can also disable talk by using the <command>mesg<\/command> command.\n<\/p>\n<p>\nIt is common practice to use a couple of terms\nfrom radio communication when using talk. Because you cannot always tell when\nsomeone is finished writing, it is common to end the line with -o (or use a\nseparate line) to indicate that your turn is “over.” When you are\nfinished with the conversation and wish to end it, use oo (over and\nout).\n<\/p>\n<question id=\"154\" text=\"Unlike write, the wall command will still work when the user is not logged in.\" \/>\n<concept id=\"\" description=\"\" \/>\n<p>\nBoth of these mechanisms have some major problems if the user is not\nlogged in: they don’t work! Instead, there’s mail or, more accurately,\nelectronic mail (or e-mail).\n<\/p>\n<p>\nOn most <glossary>UNIX<\/glossary>\nsystems (including Linux), e-mail is\naccessed through the <concept id=\"\" description=\"\" \/>mail command. Depending on your system, the mail program may be linked to something else. On my system, the default was to link to\n<command>\/usr\/bin\/mail<\/command>.\n<\/p>\n<p>\nThere are several different programs for sending and\nviewing mail. You could use one mail program (or mailer) to send the message and\nanother to read it. Often the program that you use to read your mail is called a\nmail reader or, simply, reader. Before we go on to the more advanced mail\nprograms, I want to talk about the most common mail program and the one that is\nmost likely to be on your system. (From here on, I will be referring to e-mail\nsimply as mail.)\n<\/p>\n<p>\nMail comes in units called <i>messages<\/i>. Whether you\nuse <glossary>UUCP<\/glossary>\nor the Internet, mail is sent back and forth in messages. However, once\nthe message has reached its destination, it is usually tacked onto the end of an\nexisting mail file. There is usually one mail file per user, but that single\nfile contains all of a user’s messages (that is, all those that haven’t yet been\ndeleted).<\/p>\n<p>\nTo read your mail, you can use three primary character-based\nprograms: <command>elm<\/command>,\n<command>pine<\/command>, the default\nreader <command>mail<\/command> and on many systems\n<command>xmail<\/command>. Actually, you can use all\nthree programs to send mail as well as read it. Each program has its own\nadvantages and disadvantages. Although the mail\ninterface looks menu-driven, it simply scrolls the information across\nthe screen. Both elm and pine have much more complex menuing systems. Because\nof this, mail is easier to learn, but you can do much more with the other two programs.\n<\/p>\n<p>\nAll three programs\nunderstand the concept of a “folder” in which you can store messages.\nThis allows you to develop a hierarchy of files that is no different from the\nnormal file system. How the folders are created and managed depends on the\nprogram you are using. Therefore, I would suggest that once you decide to use a\nspecific program, stick with it because the files may not be\ncompatible.\n<\/p>\n<p>\nIn keeping with the basic premise of this section, I must treat\nthese programs as applications. Therefore, I won’t go into any more detail about\nthem. Instead, I suggest that you install all three and see which one suits your\nneeds best. If you have the space, you may consider providing all three for your\nusers. The man-pages provide a great deal of information and each program has\nits own on-line help.<\/p>\n<p>\nIf you are using\nthe <tutorial id=98>X-Windowing System<\/tutorial> and a desktop\n <glossary>environment<\/glossary>\nsuch as the <a href=\"\/\/www.kde.org\">KDE<\/a>, you have\na much larger and varied choice, such as my favorite\n<a href=\"http:\/\/kmail.kde.org\">Kmail<\/a>. Prior to using kmail, I was using\nNetscape Communicator. Although the Netscape Communicator has many useful\nfeatures, Kmail had the features I really need. Plus, I use the KDE as my\ndesktop environment and Kmail fits into the KDE architecture. (I will talk more\nabout the KDE and many of the programs when I get the time.)\n","protected":false},"excerpt":{"rendered":"<p>User Communication If you are running a multiuser system like Linux, you should expect to find other users on your system. (I guess that’s why it is a multi-user system.) Although there are many built-in mechanisms to keep users separated, … <a href=\"http:\/\/www.linux-tutorial.info\/?page_id=242\">Continue reading <span class=\"meta-nav\">→<\/span><\/a><\/p>\n","protected":false},"author":1,"featured_media":0,"parent":0,"menu_order":0,"comment_status":"closed","ping_status":"closed","template":"","meta":{"footnotes":""},"class_list":["post-242","page","type-page","status-publish","hentry"],"_links":{"self":[{"href":"http:\/\/www.linux-tutorial.info\/index.php?rest_route=\/wp\/v2\/pages\/242","targetHints":{"allow":["GET"]}}],"collection":[{"href":"http:\/\/www.linux-tutorial.info\/index.php?rest_route=\/wp\/v2\/pages"}],"about":[{"href":"http:\/\/www.linux-tutorial.info\/index.php?rest_route=\/wp\/v2\/types\/page"}],"author":[{"embeddable":true,"href":"http:\/\/www.linux-tutorial.info\/index.php?rest_route=\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"http:\/\/www.linux-tutorial.info\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=242"}],"version-history":[{"count":1,"href":"http:\/\/www.linux-tutorial.info\/index.php?rest_route=\/wp\/v2\/pages\/242\/revisions"}],"predecessor-version":[{"id":775,"href":"http:\/\/www.linux-tutorial.info\/index.php?rest_route=\/wp\/v2\/pages\/242\/revisions\/775"}],"wp:attachment":[{"href":"http:\/\/www.linux-tutorial.info\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=242"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}