linux crash course chapter 02 3

Chapter 2: Getting Started Logon to Logout In this chapter … • • • • • Logging on The Shell Superuser Getting Help Logging off How 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 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 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 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 • To view a command’s man page in a particular section: – man 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 ... 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 virtualized on Vmware ESX • We’ll use PuTTY... It Right! • bfd  BAD PASSWORD: it’s WAY too short • bfd*2  BAD PASSWORD: it is too short • 1 234 5 432 1  BAD PASSWORD: it is too simplistic/systematic • shutup!  BAD PASSWORD: it is based on a...In this chapter … • • • • • Logging on The Shell Superuser Getting Help Logging off How I start? • Console