linuxppt2

The OS is the interface between users/applications and the hardware

The core of the operating system. It manages hardware and software of the machine.

It is located on the harddrive and then loaded into RAM at boot time

Normally under a filename called "vmlinuz".

The command line interfacce. It transfers user input to the kernel.

There are multiple shells available, and each user may be running multiple shell sessions at once!

BASH (Bourne Again Shell)

Sometimes called "X", is a graphical user interface (GUI)... It is layered on top of the shell!!! Contains several components.

startx

Gnome is most popular with Red Hat/Fedora and KDE is more popular with some of the other distributions

Whenever an attempt to show a new window is made, this request is redirected to the window manager, which decides the initial position of the window. Metacity - used with Fedora and integrates well with Gnome, Compiz - for workspace spinning on a cube & Enlightenment - also used with Fedora, etc etc

User interaction with the Linux KERNEL is done through a user interface, such as the terminal. The software channel allows users to *log on and gain access* to the user interface LOCALLY or across a NETWORK. Sometimes called "virtual terminals" or "virtual consoles" cause they aren't a physical object but defined thru software.

In older comp systems a terminal was a keyboard and monitor combo (ghettofied)

... are allowed in linux, each with it's own shell. This allows multitasking at command line.

Use these key combos: ctrl+alt+f1 to logon to tty1 (the graphical interface), ctrl+alt+f2 for tty2, ctrl+alt+f3 for tty3, ctrl+alt+f4 for tty4, ctrl+alt+f5 for tty5

Applications>System Tools>Terminal

shell window!

Pseudo terminal slave... the terminal accessed by the GUI through system tools is a PTS instead of a tty terminal

By right clicking

Depending on who you login as, it will be [root@cit150linux ~] # or [root@cit150linux ~] $ for regular user accounts and # for root. Also, "~" stands for the home directory.

Stands for home directory

root = login name, cit999gpblinux = the hostname and bin = the working directory

Command [Option(s)] [Argument(s)]

Indicates the name of the program to execute

Specific letters starting with "-" appearing after the command name. It alters the way the command works, is case sensitive.

Specifies a command's working parameters, and is case sensitive

Some options in a command start with "--" instead of "-" and are usually composed of a whole word rather than just a specific letter

ls = the command, -l = the option and /bin = the argument

lists specified files in long format

clears terminal screen

resets terminal to use default terminal settings

displays info on system users

displays currently logged in users

displays currently logged in users and their tasks

displays your login name

displays #s associated with your user acct name and group names, commonly referred to as User ID's (UIDS) and Group ID's (GIDS)

displays current date and time

displays calendar for current month

exits you out of your current shell

displays info on screen

displays contents of text file

displays file type

is cancel

$ = shell variable, ~ special home directory variable, & = background command execution, ; = command termination, < << >> > = input/output redirection, | = command piping, * ? [] = shell wildcards, ' " / = command substitution, () {} = command grouping

It refers to the contents of a variable. For example, echo My Shell is $SHELL displays the contents of the SHELL variable...PS: echo My Shell is SHELL would not work without the $

"" are weak quotes, and '' are strong quotes. For example, if you want to display on the screen "You won 100.00!" you would type in .. echo 'You won $100.00!'

\ is like a strong quote but for one character

For example, this command executes the whoami command and displays its results

ex: echo My account name is `whoami`

One may display help info with several commands... man (display help pages from manual), info (often easier to read descriptio of commands), and help (for all the commands that arent listed in man or info)

Type "man" followed by a command name, to exit type q

type info followed by a command name, to exit type q

type help followed by command name

MANY commands have a help option... for instance, you can get help with the command date by typing date --help

Pages from man. 1= commands that any user can execute, 2 = linux system calls, 3 = library routines, 4 = special device files, 5 = file formats, 6 = games, 7 = macro packages, 8 = commands only executable by root, 9 = linux kernel routines, n = new commands not categorized yet.

does keyword search of the manual pages. helpful for locating appropriate command. ex: man -k echo

Use to display all man pages about a command, for ex - type these sequentially:
man -k echo (search for info about echo)
man echo (display first page found)
man -a echo (display all qualifying man pages)

Same command as man -k.

Execute command makewhatis (logged in as root) to index the man page database. Will take some time.

Command displays entries from the whatis index/database.

May use up and down arrow keys to move through the command history in order to re-execute a previous command

poweroff (powers off), halt -p (powers off after halting the system), shutdown -h +4 (halts system in 4 mins), shutdown -h now (halts system immediately), shutdown -r now (reboots system immediately), shutdown -c (cancels a scheduled shut down), halt (halts system immediately), reboot (reboots your system immediately)