Linux Basic TA for ITIS3100: Xu Fei

Agenda Linux Basic  What is Linux  Linux Kernel  Linux Family Map  Linux distribution Example  User Interfaces: GUI and CLI Linux Commands Basic  Linux File System  Directory Relationship  File Permission  Usage of ls; cat/less/more; cp; mv; rm; mkdir; chmod; su; ps; kill; man

What is Linux? Linux is a Unix-like computer operating system.  free and open source Linux is now packaged for different uses in Linux distributions Linus TorvaldsLinus Torvalds, creator of the Linux kernelLinux kernel

Kernel In computer science, the kernel is the central component of most computer operating systems (OS). operating systems

Family Map

Linux distribution Example

User interfaces Graphical user interfaces (GUI) accept input via devices such as computer keyboard and mouse and provide articulated graphical output on the computer monitor.Graphical user interfacesgraphical computer monitor Command line interfaces, where the user provides the input by typing a command string with the computer keyboard and the system provides output by printing text on the computer monitor.Command line interfaces command string

GUI in Linux Today, GNOME and KDE are the dominant solutions, and often installed by default on Linux systems.GNOMEKDE

Debian Screenshot

CLI in Linux

Agenda Linux Basic  What is Linux  Linux Kernel  Linux Family Map  Linux distribution Example  User Interfaces: GUI and CLI Linux Commands Basic  Linux File System  Directory Relationship  File Permission  Usage of ls; cat/less/more; cp; mv; rm; mkdir; chmod; su; ps; kill; man

Common Linux Command line File and file system management aliasalias · cat · chattr · cd · chmod · chown · chgrp · cksum · cmp · cp · du · df · file · fsck · fuser · ln · ls · · lsof · mkdir · mount · mv · pwd · rm · rmdir · split · touchcatchattrcdchmodchownchgrpcksum cmpcpdudffilefsckfuserlnlslsof mkdirmountmvpwdrmrmdirsplittouch Process management atat · chroot · crontab · exit · kill · killall · nice · pgrep · pidof · pkill · ps · pstree · sleep · time · top · wait · watchchrootcrontabexitkillkillallnicepgreppidof pkillpspstreesleeptimetopwaitwatch User management/ environment envenv · finger · id · logname · mesg · passwd · su · sudo · uname · uptime · w · wall · who · whoami · writefingeridlognamemesgpasswdsudo unameuptimewwallwhowhoamiwrite Text processing awkawk · comm · cut · ed · ex · fmt · head · iconv · join · less · more · paste · sed · sort · tac · tail · tr · uniq · wc · xargscommcutedexfmtheadiconvjoinless morepastesedsorttactailtruniqwcxargs Shell Shell programming basenamebasename · echo · expr · false · printf · test · true · unsetechoexprfalseprintftesttrueunset Printing: lp · Communications: inetd · netstat · ping · rlogin · nc · traceroute · Searching: find · grep · strings · Miscellaneous: banner · bc · cal · dd · man · size · yeslpinetdnetstatpingrloginnc traceroutefindgrepstringsbannerbccalddmansizeyes Alphabetical Directory of Linux Commands

You're not logged in as root, are you? Don't operate the computer as the root. You should only become the root when absolutely necessary. Create a user account for yourself now!

File System Tree View

Directory Relationship Home Directory Root Directory Parent Directory Working Directory (Current Directory)

File Permission

Explanation r = read w = write x = execute u = the owner user g = the owner group o = others (neither u, nor g) chmod to change permission

File types

ls Command Result ls List the files in the working directory ls /binList the files in the /bin directory (or any other directory you care to specify) ls -lList the files in the working directory in long format ls -l /etc /binList the files in the /bin directory and the /etc directory in long format ls -la..List all files (even ones with names beginning with a period character, which are normally hidden) in the parent of the working directory in long format

cat / less / more cat testfile less testfile more testfile What is the difference?

cp

mv

rm

mkdir The mkdir command is used to create directories. To use it, you simply type:  mkdir directory

chmod Here's how it works:  rwx rwx rwx =  rw- rw- rw- =  rwx = and so on...  rwx = 111 in binary = 7  rw- = 110 in binary = 6  r-x = 101 in binary = 5  r-- = 100 in binary = 4 chmod 600 testfile

su (substitute user) su password: debian:/home/user# exit su - password: debian:~# exit debian:~# su user What is the difference between “su” and “su –”

ps ps displays the currently running processes. Try:  ps -aux

kill kill is a command used to send simple messages to processes running on the system. By default, the message sent is the "termination" signal, which requests that the process exit. kill PID In computing, the process identifier (normally referred to as the process ID or just PID) is a number used by some operating system kernels to uniquely identify a process. Use ps to get the PID

Man (Manual page) One of the easiest ways to find out how to use many commands and some applications is through the man command.  man command-name If you are new to Linux, you might not find man pages as useful as someone who is more accustomed to their terse delivery of information. But man pages can provide information on how to use commands on your system. Even at this point, you can gain insight into your system by familiarizing yourself with the man pages. You will certainly want to know how to use them eventually. Try xman at the shell prompt, man pages in a graphical presentation.

Screenshot for “man man”

Screenshot for “man ls”