AOS Linux Tutorial. Introduction to Linux. Michael Havas Dept. of Atmospheric and Oceanic Sciences McGill University. September 15, PDF Free Download

AOS Linux Tutorial Introduction to Linux Michael Havas Dept. of Atmospheric and Oceanic Sciences McGill University September 15, 2011

Outline 1 Introduction to Linux Benefits of Linux What Exactly is Linux? The Free-Software Philosophy 2 The Graphical User Interface Cross-Platform Applications Windows Applications and Their Linux Counterparts 3 The Command-Line The Filesystem File and Directory Management Globbing Finding Files Ownership and Permissions 4 Fun Tips 5 Next Time

Why Linux? Free. Free. Scientific Software. Community. Security. Stability. Learn Linux, Learn *nix.

What is Linux? A Unix-like operating system created by Linus Torvalds in 1991. Uses the GNU set of tools developed by Richard Stallman. Free and Open source under the GPL license. Not just a product but a collection of products.

Why Free Software? When you use free software, you also get the freedom to study, copy, change and redistribute the source code. If you don t like something, change it!

Cross-Platform Applications Firefox. Thunderbird. VLC. OpenOffice. Pidgin. FileZilla. Google Earth. Picasa. Adobe Reader. Adobe Flash. Opera. Skype. Google Chrome.

Applications in Windows and Linux Type Windows Linux Web Browser Internet Explorer Firefox Email Client Outlook Thunderbird File Transfer CuteFTP Filezilla Instant Messenger MSN Messenger Pidgin Media Player Windows Media Player VLC File Browser Windows Explorer Nautilus Raster Graphics Editor Photoshop The GIMP Vector Graphics Editor Illustrator Inkscape Office Suite Microsoft Office OpenOffice PDF Viewer Adobe Reader Evince Music Player Itunes Rhythmbox More equivalent applications http://www.linuxrsp.ru/win-lin-soft/table-eng.html

The Graphical User Interface

Why use the Command-Line? Fast. Efficient. Powerful. Scripting language. Remote access. Almost Anything you can do in the GUI, you can do on the command line: Listen to music. Read email. Browse the web. Watch movies (kinda: towel.blinkenlights.nl).

The Filesystem One root to rule them all

The Filesystem Different devices, same root

Absolute vs Relative Paths Absolute vs Relative Absolute Starting from the root (/). Relative Starting from your working directory. Special Paths. The current directory... The parent of the current directory. On Linux, everything is case sensitive!

Absolute vs Relative Paths An Example

Getting Around Shortcuts Shortcuts ${HOME} Your home directory. Your home directory. mhavas My home directory.

Getting Around Commands ls List contents of directory. cd Change directory. pwd Print working/current directory. Tab-completion is your friend

File and Directory Management Commans touch file Creates a file called file. mkdir dir Creates a directory dir. rm file Remove a file. rmdir dir Remove an empty directory dir. cp src dst Copies file from src to dst. mv src dst Moves file/dir from src to dst. du file Prints size of file in bytes. file file Prints what type of file file is. ln file link Creates a hard or soft link between file and link.

File and Directory Management Useful Options Commands mkdir -p path Creates all directories if they do not exist in path. rm -r dir Removes all files and directories in dir including dir cp -a srcdir dstdir Copies directory and contents from srcdir to dstdir. ls -l Same as ls but gives more information. du -hs dir Prints size of directory and all contents in human-readable format. Getting Help For useful options and detailed help for almost any program, you can look at the manual for that specific command using: man command.

File and Directory Management Links Soft Links Command: ln -s file link Creates a named link between file and link. Hard Links Command: ln file link Creates a physical link between file and link. Deletion is handled differently

Globbing Allows you to select many items at once. * Match anything at any length.? Match one character. [ab] Match characters a or b. {blah,foo} Match words blah or foo. ˆglob Match anything but glob.

Globbing Examples [mhavas@lappy tmp]$ ls a.1 b.1 c.1 t2.sh test1.txt [mhavas@lappy tmp]$ ls t?.sh

Globbing Examples [mhavas@lappy tmp]$ ls a.1 b.1 c.1 t2.sh test1.txt [mhavas@lappy tmp]$ ls t?.sh t2.sh

Globbing Examples [mhavas@lappy tmp]$ ls a.1 b.1 c.1 t2.sh test1.txt [mhavas@lappy tmp]$ ls t?.sh t2.sh [mhavas@lappy tmp]$ ls [ab]*

Globbing Examples [mhavas@lappy tmp]$ ls a.1 b.1 c.1 t2.sh test1.txt [mhavas@lappy tmp]$ ls t?.sh t2.sh [mhavas@lappy tmp]$ ls [ab]* a.1 b.1

Globbing Examples [mhavas@lappy tmp]$ ls a.1 b.1 c.1 t2.sh test1.txt [mhavas@lappy tmp]$ ls t?.sh t2.sh [mhavas@lappy tmp]$ ls [ab]* a.1 b.1 [mhavas@lappy tmp]$ ls [a-c]*

Globbing Examples [mhavas@lappy tmp]$ ls a.1 b.1 c.1 t2.sh test1.txt [mhavas@lappy tmp]$ ls t?.sh t2.sh [mhavas@lappy tmp]$ ls [ab]* a.1 b.1 [mhavas@lappy tmp]$ ls [a-c]* a.1 b.1 c.1

Globbing Examples [mhavas@lappy tmp]$ ls a.1 b.1 c.1 t2.sh test1.txt [mhavas@lappy tmp]$ ls t?.sh t2.sh [mhavas@lappy tmp]$ ls [ab]* a.1 b.1 [mhavas@lappy tmp]$ ls [a-c]* a.1 b.1 c.1 [mhavas@lappy tmp]$ ls [^ab]*

Finding Files Finding Files Find files using locate locate word Find file or directory that has word in it. Fast but only search a database. Database is refreshed once a day using updatedb Find files using find find path -iname *word* Finds files and directories recursively starting in path path that have word in their filename. Very useful command and has lots and lots of options.

Finding Files Useful arguments to find More on the find command find. -type d Find all directories under the current directory. find. -type f Find all files under the current directory. find. -mtime 1 Find that were created in the past 24 hours. find. -daystart -mtime +0 -mtime -3 Find files created between yesterday and the day before. find. -size -5k Find files less than 5 kilobytes. Operating on found files find. -type d -exec chmod 755 {} \; Find all directories under the current directory and execute chmod 755 on them. find. -type f -exec chmod 644 {} \; Find all files under the current directory and execute chmod 755 on them.

Finding Files Finding Programs The path environment variable path tells the shell where to look for files. You can execute a program in your path by typing program. Programs not in your path must include the program s path. For example, /aos/shared/bin/matlab You can see your path by issuing env $PATH Searching through your path which program Will show the location of the first program named program in your path. which -a program Will show all programs names program in your path. Note that only the first will run if you type program. whereis program Will search for a program s binary, source and help in their standard locations.

Ownership and Permissions Owner [mhavas@lappy tmp]$ ls -l -rw-rw-r--. 1 mhavas mhavas 0 2009-09-23 15:18 a.1 -rw-rw-r--. 1 mhavas mhavas 0 2009-09-23 15:18 b.1 -rw-rw-r--. 1 mhavas mhavas 0 2009-09-23 15:18 c.1 -rw-rw-r--. 1 mhavas mhavas 0 2009-09-23 15:18 t2.sh -rw-rw-r--. 1 mhavas mhavas 0 2009-09-23 15:18 test1.txt

Ownership and Permissions Group [mhavas@lappy tmp]$ ls -l -rw-rw-r--. 1 mhavas mhavas 0 2009-09-23 15:18 a.1 -rw-rw-r--. 1 mhavas mhavas 0 2009-09-23 15:18 b.1 -rw-rw-r--. 1 mhavas mhavas 0 2009-09-23 15:18 c.1 -rw-rw-r--. 1 mhavas mhavas 0 2009-09-23 15:18 t2.sh -rw-rw-r--. 1 mhavas mhavas 0 2009-09-23 15:18 test1.txt

Ownership and Permissions Changing Ownership Commands for changing ownership chown user file Change the ownership of file to user. chgrp group file Change the group ownership of file to group. chown user:group file Change the ownership of file to user user and group group. Both commands can take a -R argument to apply the change recursively.

Ownership and Permissions Permissions [mhavas@lappy tmp]$ ls -l -rw-rw-r--. 1 mhavas mhavas 0 2009-09-23 15:18 a.1 -rw-rw-r--. 1 mhavas mhavas 0 2009-09-23 15:18 b.1 -rw-rw-r--. 1 mhavas mhavas 0 2009-09-23 15:18 c.1 -rw-rw-r--. 1 mhavas mhavas 0 2009-09-23 15:18 t2.sh -rw-rw-r--. 1 mhavas mhavas 0 2009-09-23 15:18 test1.txt

Ownership and Permissions Permissions user group other r w x r w x r w x File Permissions r Read file. w Write file. x Execute file. Group Permissions r List contents. w Write into. x Enter.

Ownership and Permissions Changing Permissions Commands for changing permissions chmod perms file Changes the permission of file file to perms. perms? what perms? user group other r w x r w x r w x [mhavas@lappy tmp]$ ls -l a.1 -rw-r--r--. a.1 [mhavas@lappy tmp]$ chmod g+x,o+x a.1 [mhavas@lappy tmp]$ ls -l a.1

Fun Tips cd - Go back to the last directory you visited. cd Go to your home directory. mkdir -p dir/{dir1,dir2,dir3} Create multiple nested directories at once.

Next Time Next Time More on the command-line. Shell scripting in bash. Gnuplot. Suggested topics.

AOS Linux Tutorial. Introduction to Linux. Michael Havas Dept. of Atmospheric and Oceanic Sciences McGill University. September 15, 2011