Chapter 2:Getting Started

Logon to Logout

In this chapter …• Logging on

• The Shell

• Superuser

• Getting Help

• Logging off

How do I start?• Console vs. terminal vs. terminal emulator

• Text-based vs. graphical

• Where’s the box at?

Consoles and terminals• Monitor, keyboard (and maybe mouse) attached

to the box

• The console often locked away in a closet or server farm somewhere

• Terminals usually found in mainframe environment

• Recently ‘thin clients’ gaining popularity again

Terminal Emulation• Using a separate system, connect a virtual

terminal to the server

• telnet, ssh, X Windows

• Most common way to interact with a Linux/UNIX machine

From Windows environment• telnet built in, but insecure (cleartext passwords)

• For ssh, need a supported terminal emulator– PuTTY, TeraTerm Pro, SecureCRT

• For remote X Windows, need a local X Server running– cygwin, XWin-32, Exceed, Xming

Here at Solano College• Our server is racked in the campus MDF

• RedHat Enterprise Linux 5 virtualized on Vmware ESX

• We’ll use PuTTY and cygwin

Logging on• Your username will be your My.Solano username

• Your password is by default set to your SCC ID, all 9 digits (pad front with zeroes)

• *Remember* Linux/Unix is case sensitive

Change your password first• To secure your account, change your password

immediately

• Type passwd and hit enter

• You will be prompted to enter your current password

• You will be prompted twice for a nice password

• Must be a good password!

What Makes a Good Password?• At least 6 characters long (8+ is even better)

• Not be a dictionary word in any language (including Klingon!)

• Not a name, place or date of personal significance

• Contains mixed case, numbers, and special characters

Do It Right!• bfd BAD PASSWORD: it’s WAY too short

• bfd*2 BAD PASSWORD: it is too short

• 123454321 BAD PASSWORD: it is too simplistic/systematic

• shutup! BAD PASSWORD: it is based on a dictionary word

The Shell• Command interpreter

• Translates commands issued by user into commands sent to the kernel

• Common shells: bash, tcsh, csh, zsh, ksh

• Linux default is bash (Bourne Again Shell)

What shell am I running?• Type ps right after logging on

• finger yourself

Correcting errors• Erase a character: BACKSPACE, DEL or

CTRL-H

• Erase a word: CTRL-W

• Erase a line (line kill): CTRL-U or CTRL-X

Other key commands• Terminate (interrupt key): CTRL-C

• Suspend job: CTRL-Z

• Show jobs: jobs

• Stop job: kill –KILL %job_no

• Command history: UP and DOWN

Administrative privileges• root or superuser

• Full read/write access to filesystem

• Can execute privileged commands and programs

• Use sparingly and with extreme caution

Getting help• Most GNU commands and utilities have built in

help and usage information

• --help (sometimes -h or -help)

• Too much information? Pipe results to less or more– ls --help | less

man Pages• man program_name

• Displays online documentation, formatted with a pager

• SPACE to advance, q to quit

• Depending on the system sometimes you can also use PAGE UP/DOWN

man Pages con’t• Divided into ten sections based on type

• User commands in section 1

• To view a command’s man page in a particular section:– man 8 su

info• info program_name

• GNU online documentation

• SPACE to scroll

• ENTER to select a subtopic

• q to quit

At the end of the day• To log out, press CTRL-D or type exit

• If you have suspended jobs it will warn you before you log out