ADVENTURES
IN TEXT
If youenterthe IP addressof the targetcomputer
andclickopen,you’llbe promptedto allowthe
installationof the server’s key. Thisis to ensurethat
youonlyconnectto a knownsecurehost.Answer‘yes’
to this,andthenyou’llsee the loginscreen.Login
withyourusernameandpassword,andyoushouldbe
lookingat an ssh terminalwindow.Onceconnectedto a remotessh terminal,you’re
loggedin as if youweresittingat the other
computer’s terminalscreen.You canmovearound
the filesystem,executecommandsandgenerallydo
anythingthatyouwant.
To leave,simplytypeexit.to the days before GUI-basedcomputers,where it would
actuallybe a physicalterminal,runninga text-basedsession
on a mainframecomputer. Early versionslacked even a screen,
boastingonly a keyboard and printer, sometimescalled a
Teletype terminal(TTY).
There are many terminalemulatorsfor Linux, and any distro
will offer at least one. Within the terminalsits the ‘shell’ text
environment.There are many of these available,but among
the most widely used in Linux is bash (the bourne again shell,
an enhancedversionof the originalUnix sh shell, which was
writtenby Steve Bourne). This is the one that I will be referring
to in these articles.
The hardware required for this series is minimal:an old PC
runningLinux or a RaspberryPi would be ideal. If you lack a
spare monitor, once installed,the OS will quite happilyrun
headless,and you can connectover the network.
Practisingon a safe platformrather than a live systemis
recommended.Althougha Linux systemis seldomirretrievable,
until you becomeconfidentwith its operation,it’s reassuringto
know that you can easily start afresh.
A RaspberryPi is perfectfor this and uses very little power.
You can keep a copy of the systemSD card to hand for easy
reinstallationif you break things,and you’re not gamblingwith
your main PC’s data.
If you don’t have any suitablehardware, a virtual machine
host such as Virtualboxcan be used on Windows or Linux,
runninga Linux virtual guest.GettingStarted
When you open a terminalwindow, the first thing you see will
look somethinglike the image below. The line with the flashing
cursor at the end is called a ‘commandprompt’, becauseiA typicalterminalwindow
iThesshkeymessage iThesshloginscreen