RemoteAccesstoUnixMachines
AlvinR.Lebeck
DepartmentofComputerScience
DepartmentofElectricalandComputerEngineering
DukeUniversity
Overview
WeareusingOITLinuxmachinesforsomehomeworkthissemester.Therefore,youneed
to ensure your account is activated, that you can remotely access the machines, and that
you become familiar with using Linux to create files, move around the directory (folder)
structure,etc.Thistutorialisaimedatgettingyouuptospeedontheseaspectsearly,so
youcanhitthegroundrunning.
MachineNames
Themachineswewillusearenamedlogin-teer-<##>.oit.duke.edu(where<##>is01-45)
andareaccessibleeitherbydirectlyloggingintothemachinesintheTeerbuilding,ormore
commonlyusingremoteaccessusinglogin.oit.duke.edu(seebelow).Themachinenames
are login-teer-01.oit.duke.edu, login-teer-02.oit.duke.edu, … login-teer-45.oit.duke.edu.
Notethatthemachines1-9requiretheleading0.
RemoteAccesstoMachines
AconvenientwaytoaccessalinuxmachineisremotelyovertheInternet.Themainitem
necessaryforthisisasecureshellclient,butwewillalsoutilizeX-windowssowecanrun
programs with graphical interfaces (GUIs). We will use login.oit.duke.edu to remotely
connecttooneoftheteermachines:login.oit.duke.eduisafront-endaliasthatdynamically
selectsoneofthephysicalteermachinestoconnectto.
MACOS
1. DownloadandinstallXquartzfrom http://xquartz.macosforge.org.
2. LogoutofyourMAC
3. LogintoyourMAC
X-windowsisnowreadyforuseonyourMAC.Nextupisthesecureshellclient,ona
MACthisiseasysinceithasashellbuiltinviatheTerminalApplication.
4. OpentheTerminalApp.YoucanfindTerminalintheApplications/Utilitiesfolder
orbysearchinginSpotlightforTerminal.
5. At the command prompt type ssh–[email protected] where netID is your
Duke netID. This command initiates a secure shell connection to one of the teer
machines. If this is the first connection that you’ve made to a particular machine
you will receive a warning about the authenticity of the host and RSA key
fingerprint. This is expected behavior for first-time connections. If you typed the
machinenamecorrectly,youcanjusttypeyesandtheappropriateinformationwill
be added to your local machine, and you shouldn’t see the error again on
subsequentconnectionstothissamemachine.
6. Enter your password. Note the characters you type are not displayed on your
screen,neitherareany***correspondingtothecharacters.So,ifloginfailsyoumay
havetotryagain.
Ta-dah! You are now successfully connected to a remote machine over the Internet.
Goto the “At the remote machine command prompt” section after the Windows
informationbelow.
Windows
1. DownloadandinstallMobaXtermathttp://mobaxterm.mobatek.net/
2. StartMobaXterm(i.e.,runtheprogram)
3. ClickSessionintheupperleftofthemobMobaXtermwindow
a. You should get a popup window with choices across the top for type of
session.ChooseSSH.
b. ForRemotehostenterlogin.oit.duke.edu
c. Click the specify username checkbox, and enter your Duke NetID for the
username.
d. ClickOK.Thiscreatesasessionforlateruseandalsoconnectsyoutooneof
theteermachines,withapromptforyourpasswordintheshellwindow.
4. Typeyourpasswordattheprompt.Notethecharactersyoutypearenotdisplayed
onyourscreen,neitherareany***correspondingtothecharacters.So,ifloginfails
youmayhavetotryagain.
5. ThenexttimeyoustartMobaXterm,youcanjustdoubleclickthelogin.oit.duke.edu
sessioninthesavedsessionstabtoconnecttoaDukeLinuxmachine.
Ta-dah!YouarenowsuccessfullyconnectedtoaremoteLinuxmachineovertheInternet.
I’llleaveyoutoexplorethecapabilitiesofMobaXtermonyourown.
Linux
If you are using Linux then you probably don’t need these instructions, but just in case…
Simplystartatstep4oftheMacinstructions.
1. OpenaTerminal
2. TypeSSH–[email protected]
Attheremotemachinecommandprompt
YounowhaveaterminalsessionthatisconnectedtooneoftheDukeLinuxmachiens(e.g.,
login-teer-15.oit.duke.edu).
You should see a command prompt that is something like “netID@login-teer-15
[production] ~ $” with a blinking cursor after the $. Note that you may have a slightly
differentprompt,e.g.,witha>or%insteadofthe$,notabigdeal…lookfortheblinking
cursor. Your specific prompt may differ from the screen grabs below due to some
customizationsI’veadded.
1. Type date at this prompt, and press return, this is a unix command to display
today’sdate,asshownbelow.
2. Typextermattheprompt.Thisshouldopenawindowonyourmachine’sscreen
thatgivesyouanotherterminalontheremotemachine.Noteyoumayneedtotab
betweenwindowssinceitmaynotautomaticallycometothefrontofyourdesktop.
If this fails, you’ve done something wrong in setting up X-windows, please review
thestepsaboveaccordingtoyouroperatingsystem.
[production]~$xterm
3. Clickinthextermwindowtoactivateit.Closethenewxtermwindowbytypingexit
at the prompt ([production] ~ $ exit) within the xterm window or by clicking the
closebuttonofthextermwindow.
4. Background jobs are often useful since they allow you to use multiple windows
simultaneously. For example, let’s say you want to have two xterms running and
usebothalongwiththeoriginalsessionwindow.Toachievethisyoucantype:
[production]~$xterm&
[production]~$$xterm&
The & tells unix to run the specified program in the background (in this case it is
xterm).Nowyoucanclickaroundandtypedateineachofthethreewindows
5. Closethetwoxtermwindows(typeexitinthemorclicktheclosebutton).
6. TypelogoutatthepromptinyourinitialsessionwindowtoendtheSSHconnection
anddisconnectfromtheremotemachine([production]~$logout).
UnixTutorial
YouarenowreadytogothroughtheUnixtutorialavailableat
http://www.cs.duke.edu/~alvy/courses/unixtut.