V2012.13
Agenda
• Old Business
– Delete Files
• New Business
– Week 8 Topics:
• Complete Cinnamon & Applet Install
• Linux Intro (continued)
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New Business
• Complete Cinnamon & Applet Installs
• Intro to Linux
– Basic Commands
– Install Additional Software
– Practice Exercises
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Basic Commands
• Commands take the following form:
<Command> <Switches> <Parameters> <Target>
• Switches: single letters, preceded by a hyphen,
that adjust what the command does
• Parameters: things that the command needs to
know in order to work
• Target: the thing (such as a file) that the
command will be applied
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Basic Commands
• Let’s look at an example:
$ ls -l /home/seighman
Target
Switch
Command
This command tells the command line to list, in long format, the contents of the
directory “/home/seighman”. The command is “ls”; the switch “-l” tells Linux that
you want the list in long format; and the target of this command is the directory
“/home/seighman”. In this example, there are no parameters, so that part of the
command is just skipped
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Basic Commands - man
• So, how do I know what switch to use?
– manpages are your friend
$ man ls
LS(1)
User Commands
LS(1)
NAME
ls - list directory contents
SYNOPSIS
ls [OPTION]... [FILE]...
DESCRIPTION
List information about the FILEs (the current directory by default). Sort entries
alphabetically if none of -cftuvSUX nor --sort is specified
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Basic Commands
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•
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•
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pwd
ls
cd
mkdir
rmdir
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Basic Commands - pwd
• ‘pwd’
$ pwd
/home/seighman
• The you are here sign can be displayed with the pwd
command (Print Working Directory)
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Basic Commands - cd
• ‘cd’
$ cd
$ pwd
/home/seighman
• You can change your current directory with the cd
command (Change Directory)
• Entering ‘cd’ will always return you to your home
directory
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Basic Commands - cd
• Some ‘cd’ examples:
$ cd /
• Will take you to the ‘root’ directory
$ cd • Will return you to the previous directory location
$ cd ~
• Will return you to your home directory
$ cd ..
• Move one level above your current directory in the directory
tree
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Absolute and Relative Paths
• When you type a path starting with a slash (/), then the
root of the file tree is assumed
• If you don't start your path with a slash, then the current
directory is the assumed starting point
$ pwd
/home/seighman
$ cd home
bash: cd: home: No such file or directory
$ cd /home
$ pwd
/home
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Linux File System
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Repeating and Editing Commands
• Use the Up-arrow key to retrieve a command you issued
before
• You can move up and down using arrow keys to get
earlier and later commands
• The Left-arrow and Right-arrow keys let you move
around inside a single command
• Combined with the Backspace key, these let you
change parts of the command and turn it into a new one
• Each time you press the Enter key, you submit the
modified command to the terminal and it runs exactly as
if you had typed it from scratch
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Basic Commands - ls
• Let’s focus on ‘ls’
$ ls –l
drwxrwxr-x 5 seighman seighman 4096 Jan 3 11:27 linux
d = directory
l = link
- = file
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Basic Commands
$ ls –l
drwxrwxr-x 5 seighman seighman 4096 Jan 3 11:27 linux
• The nine characters that follow, describe access rights
for the owner (user), group and the world (everyone
else who may be able to access the file), in that order,
each with three characters
• The characters used here are:
r = Read access
w = Write access
x = Permission to execute the program
- = No access of this type
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Basic Commands – mkdir & rmdir
• Create your own directories with mkdir
• You have to give at least one parameter to
mkdir, the name of the new directory to be
created
Important Note: Linux is case sensitive, this
means that FILE1 is different from file1 and
directory1 is different from Directory1
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Basic Commands – mkdir
$ mkdir test
$ ls
test
• When given the option -p, then mkdir will create parent
directories as needed
$ mkdir -p techcrew/scripts
$ ls
test techcrew
$ cd techcrew/
$ ls
scripts
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Basic Commands – rmdir
$ rmdir test
$ ls
• When given the option -p, rmdir will recursively remove
directories
$ rmdir -p techcrew/scripts
$ ls
Warning: be careful when deleting files and
directories!
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Practice Exercises
• Work through the exercises here:
http://ahstechcrew.org/docs/BasicCommandsPractice1.pdf
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Super User
• The “sudo” command introduces the “superuser” or “root
user”
• The term “root” is the name for the main administrator in
a “Unix-like” system, such as Linux
• There are many commands that only the root user can
run
• Depending on the version of Linux you are using, you
will either have to log on as the root user or prefix your
command with “sudo”. The default Debian distribution of
Linux, for instance, has no root password set. So you will
have to use the “sudo” command
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Super User
• By using “sudo”, you’re saying, “Do the following
command as the root user”
• When you do this, you will be asked for your password
and, if you have the system permissions of a root user
(commonly called “being in the admin group”), then the
command will be run
• If you don’t have root permissions, you will get an error
message
WARNING: be very careful executing commands as
root (sudo), you can easily render your system
unuseable!
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Installing Software
• Installing software on Linux is a broad subject because
each version of Linux has its own way of doing things
• Most are variations on apt-get (Advanced Packaging
Tool), used by Debian, Ubuntu, and related distributions)
• yum (Yellowdog Update Manager), used by Fedora and
related distributions
• The basic syntax is:
$ sudo apt-get install <packagename>
$ sudo yum install <packagename>
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Using apt-get to Manage Software
• To install a software package:
$ sudo apt-get install <packagename>
• To update the local package database:
$ sudo apt-get update
• To install all available newer versions of packages:
$ sudo apt-get upgrade
• To remove a package:
$ sudo apt-get remove <packagename>
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Ubuntu Setup
• Install Ubuntu Tweak
– Open a ‘terminal’
– Enter the following commands:
$ sudo add-apt-repository ppa:tualatrix/ppa
$ sudo apt-get update
$ sudo apt-get install ubuntu-tweak
– You may need to logout and login again
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Basic Commands 2
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•
•
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file
touch
cp
rm
mv
rename
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