■The UNIX Shell
■ Environment variable
■ Source Code, Object Code, Binary Code, Library……x
■ Source Code, Object Code, Binary Code, Library
■ Filtering
■ networking, UNIX Networking Tools
■ Security
■ X Window System
filtering is a way to process text in a usable manner for the goal that is in mind.
some filtering utilities
cat(1) - concatenate files cut(1) - cut text grep(1) - globally search for regular expression and print head(1) - print first “n” lines of output sed(1) - stream editor sort(1) - sort output tail(1) - print last “n” lines of output tr(1) - translate characters uniq(1) - filter out duplicate lines from sorted file wc(1) - word count
lab46:~$ cat sample.db name:sid:major:year:favorite candy* Jim Smith:105743:Economics:Sophomore:Lollipops* Adelle Wilson:594893:Sociology:Junior:Ju-Ju Fish* Sarah Billings:938389:Accounting:Freshman:Tic-Tacs* Eric Vincent:1001119:Biology:Freshman:Lollipops* Linus Torvalds:4432001:Computer Science:Senior:Snickers* Alan Cox:40049300:Computer Science:Senior:Whoppers* Alan Turing:40030333:Computer Science:Senior:Rock Candy* Eric Vincent:1001119:Biology:Freshman:Lollipops* John Doe:0000000:Unknown:Freshman:unknown* Leet Haxzor:31337:Business:Sophomore:Gobstoppers* Matthew Green:439478:Philosophy:Junior:Necco Wafers* Megan Tanner:372233:Physics:Junior:Zero Bar* Junior Mint:2228484:Liberal Arts:Junior:Junior Mints* Alan Wilson:22908948:Economics:Freshman:Whoppers* Kris Warner:8383833:Biology:Senior:Mars Bar* Jill Ashley:9939392:Chemistry:Freshman:Warheads* Francois Laroux:93938383:Anthropology:Sophomore:Bubblegum* lab46:~$ cat sample.db | grep Biology Eric Vincent:1001119:Biology:Freshman:Lollipops* Eric Vincent:1001119:Biology:Freshman:Lollipops* Kris Warner:8383833:Biology:Senior:Mars Bar* lab46:~$ cat sample.db | grep Biology | grep Lollipops Eric Vincent:1001119:Biology:Freshman:Lollipops* Eric Vincent:1001119:Biology:Freshman:Lollipops* lab46:~$ echo "hello there:this:is:a:bunch of:text." | cut -d":" -f1 hello there lab46:~$ echo "hello there:this:is:a:bunch of:text." | cut -d":" -f2 this lab46:~$ echo "hello there:this:is:a:bunch of:text." | cut -d":" -f3 is lab46:~$ echo "hello there:this:is:a:bunch of:text." | cut -d":" -f1,6 | sed -e 's/:/ /g' hello there text. lab46:~$ sort sample.db sorts alphabetically Adelle Wilson:594893:Sociology:Junior:Ju-Ju Fish* Alan Cox:40049300:Computer Science:Senior:Whoppers* Alan Turing:40030333:Computer Science:Senior:Rock Candy* Alan Wilson:22908948:Economics:Freshman:Whoppers* Eric Vincent:1001119:Biology:Freshman:Lollipops* Eric Vincent:1001119:Biology:Freshman:Lollipops* Francois Laroux:93938383:Anthropology:Sophomore:Bubblegum* Jill Ashley:9939392:Chemistry:Freshman:Warheads* Jim Smith:105743:Economics:Sophomore:Lollipops* John Doe:0000000:Unknown:Freshman:unknown* Junior Mint:2228484:Liberal Arts:Junior:Junior Mints* Kris Warner:8383833:Biology:Senior:Mars Bar* Leet Haxzor:31337:Business:Sophomore:Gobstoppers* Linus Torvalds:4432001:Computer Science:Senior:Snickers* Matthew Green:439478:Philosophy:Junior:Necco Wafers* Megan Tanner:372233:Physics:Junior:Zero Bar* Sarah Billings:938389:Accounting:Freshman:Tic-Tacs* name:sid:major:year:favorite candy* lab46:~$ head -5 sample.db "print first 5 lines" tail does opposite prints last -n lines of file specified name:sid:major:year:favorite candy* Jim Smith:105743:Economics:Sophomore:Lollipops* Adelle Wilson:594893:Sociology:Junior:Ju-Ju Fish* Sarah Billings:938389:Accounting:Freshman:Tic-Tacs* Eric Vincent:1001119:Biology:Freshman:Lollipops*
Security is ability to allow and/or deny access to information that is vital to any multi-user system.
To be able to change permissions, allow access for new directories created along with new files is just some of the basic but must be taken into account. below is a command line which will display the umask
lab46:~$ umask 0022 lab46:~$ touch newfile lab46:~$ ls -l newfile -rw-r--r-- 1 rmatsch lab46 0 Apr 21 12:18 newfile lab46:~$
This means your default umask is set to this meaning that any files you make will have this minused the full permissions so a normal file full permission would be 666 but now when a new file is created thanks to umask the permissions on the file in octal are 644 which mean the owner can read and write to the file and everyone else can only read and same for group.
lab46:~$ mkdir newdirect lab46:~$ ls -ld newdirect drwxr-xr-x 2 rmatsch lab46 6 Apr 21 12:19 newdirect
full permission on a directory is 777 so 777 -22 = 755 which is show above with the owner having read write execute and group and world having only read and execute privileges.so umask is a very important thing to know if you are considering security of the system and users.
When you don't have access:
lab46:~$ cd /root -bash: cd: /root: Permission denied lab46:~$ chmod 077 newdirect "change newdirect's permissions to 077" lab46:~$ cd newdirect -bash: cd: newdirect: Permission denied
The Unix shell is a command-line interpreter that provides a user interface for Unix/linus operating systems. Users directly operate with the computer by entering commands execute, create, delete, and various other operation. There is no “ button clicking like windows computers”
At a command line interpreter such as bash or various other you can search through files, list files,create new files, copy files, delete files, make directories, and so on.Below is a demonstration of the various nothing i talked about just showing you that all task or “moving around the sytem is done through commands.
lab46:~$ ls 2 badname.tgz newdirect CCC.sh bin phenny CCCclasses.sh class_notes phenny.tar.bz2 Desktop classlog.c regex.html Documents count.c sample.db Downloads data spring2010-20091022.html Maildir fall2010-20100315.html spring2010-20101113.html Music fall2010-20101113.html spring2011-20101105.html Pictures fall2011-20110417.html spring2011-20101113.html Public file spring2012-20111103.html Templates index.html src Videos lab1 stdout archives labD.sh winter2011-20101113.html badname motd lab46:~$ cp count.c count.xxxxxxxxxxxxxx lab46:~$ rm count.c rm: remove regular file `count.c'? y lab46:~$ mkdir newdirect2 lab46:~$ touch newfile lab46:~$ ls 2 bin newfile CCC.sh class_notes phenny CCCclasses.sh classlog.c phenny.tar.bz2 Desktop count.xxxxxxxxxxxxxx regex.html Documents data sample.db Downloads fall2010-20100315.html spring2010-20091022.html Maildir fall2010-20101113.html spring2010-20101113.html Music fall2011-20110417.html spring2011-20101105.html Pictures file spring2011-20101113.html Public index.html spring2012-20111103.html Templates lab1 src Videos labD.sh stdout archives motd winter2011-20101113.html badname newdirect badname.tgz newdirect2 lab46:~$ grep hey regex.html <td NOSAVE><b><u><font size=+1>Objective:</font></u></b> To become familiar with the UNIX command line through exposure to some simple commands. The student will also be presented with traditional UNIX conventions they are expected to become familiar with and use throughout the semester.</td> How have they changed?</td> lab46:~$ cd .. lab46:/home$ ls bherrin2 dh018304 hshaikh jsmit176 mdecker3 rmatsch tp001498 bhuffner dherman3 hwarren1 jstrong4 mdittler rmoses triley2 bkenne11 dlalond1 ian jsulli34 mearley1 rnewman ts004985 bobpauljr dmay5 javery9 jtongue2 mgough rpetzke1 wedge bort dmckinn2 jbaez jtreacy mguthri2 rraplee wezlbot bowlett1 dmurph14 jbamper jtripp mhenry9 rrichar8 wfischba brian dpadget8 jbarne13 jv001406 mkellogg rsantia4 wknowle1 brobbin4 dparson3 jbesecke jvanott1 mkelsey1 rshaw8 wroos bstoll dpotter8 jblaha jwalrat2 mmatt rthatch2 ystebbin btaber2 dprutsm2 jblanch1 jwhitak3 mowens3 ryoung12 zlittle bwheat drobie2 jbrant jwilli30 mp018526 sblake3 zmccann bwilso23 ds000461 jbrizzee jwilso39 mpage9 sc000826 zward lab46:/home$ cd rmatsch lab46:~$ cd src lab46:~/src$ ls Makefile cprog hello1 hello1.c helloC helloC.c submit unix lab46:~/src$ cd unix lab46:~/src/unix$ ls arc.tar.gz cs4.txt cs9.txt lab0.txt lab5.txt laba.txt contact.info cs5.txt csA.txt lab1.txt lab6.txt link.sh cs1.txt cs6.txt csB.txt lab2.txt lab8.txt scripting cs2.txt cs7.txt csC.txt lab3.txt lab9.txt shell cs3.txt cs8.txt devel lab4.txt labC.txt unix_html_stuff lab46:~/src/unix$
environment variables are significant and can be thought of in a sense to create the operating environment in which a process runs. environment variables set at login are valid for the duration of the session. Environment variables have UPPER CASE as opposed to lower case which are shell variables.
USER (your login name) HOME (the path name of your home directory) HOST (the name of the computer you are using) ARCH (the architecture of the computers processor) DISPLAY (the name of the computer screen to display X windows) PRINTER (the default printer to send print jobs) PATH (the directories the shell should search to find a command)
lab46:~$ echo $HOME /home/rmatsch lab46:~$ echo $PATH /home/rmatsch/bin:/usr/local/bin:/usr/bin:/bin:/usr/bin/X11:/usr/games lab46:~$ echo $OSTYPE linux-gnu lab46:~$ echo $USER rmatsch lab46:~$ echo $home lab46:~$
a software system which provides a basis for GUI's and has good input device capability for computers. basically it is used to build graphical user interfaces for unix like operating systems originally designed for network connection.
tools used to gain networking information such as the host you are connected to and various other network data that may be useful.
some of the two most important networking tools i think are netstat, ping below are example of them to find information on dns server to see if packets or being sent and network information.
lab46:~$ ping localhost PING localhost.localdomain (127.0.0.1) 56(84) bytes of data. 64 bytes from localhost.localdomain (127.0.0.1): icmp_req=1 ttl=64 time=0.045 ms 64 bytes from localhost.localdomain (127.0.0.1): icmp_req=2 ttl=64 time=0.037 ms 64 bytes from localhost.localdomain (127.0.0.1): icmp_req=3 ttl=64 time=0.038 ms 64 bytes from localhost.localdomain (127.0.0.1): icmp_req=4 ttl=64 time=0.036 ms ^C --- localhost.localdomain ping statistics --- 4 packets transmitted, 4 received, 0% packet loss, time 2997ms rtt min/avg/max/mdev = 0.036/0.039/0.045/0.003 ms netstat Active Internet connections (w/o servers) Proto Recv-Q Send-Q Local Address Foreign Address State tcp 0 0 lab46.offbyone.la:60002 irc.offbyone.lan:ircd ESTABLISHED tcp 0 0 lab46.offbyone.lan:ssh mobile-198-228-20:58895 ESTABLISHED tcp 0 0 lab46.offbyone.la:47089 irc.offbyone.lan:ircd ESTABLISHED lab46:~$ netstat -ta Active Internet connections (servers and established) Proto Recv-Q Send-Q Local Address Foreign Address State tcp 0 0 *:ssh *:* LISTEN tcp 0 0 *:35801 *:* LISTEN tcp 0 0 *:nfs *:* LISTEN tcp 0 0 *:3939 *:* LISTEN tcp 0 0 *:3333 *:* LISTEN tcp 0 0 lab46.offbyone.lan:5000 *:* LISTEN tcp 0 0 lab46.offbyone.lan:5007 *:* LISTEN tcp 0 0 *:59343 *:* LISTEN tcp 0 0 *:sunrpc *:* LISTEN tcp 0 0 *:csync2 *:* LISTEN tcp 0 0 lab46.offbyone.lan:4242 *:* LISTEN tcp 0 0 lab46.offbyone.la:60002 irc.offbyone.lan:ircd ESTABLISHED tcp 0 0 lab46.offbyone.lan:ssh mobile-198-228-20:58895 ESTABLISHED tcp 0 0 lab46.offbyone.la:47089 irc.offbyone.lan:ircd ESTABLISHED tcp 0 0 lab46.offbyone.la:47998 irc.offbyone.lan:ircd ESTABLISHED tcp 0 0 lab46.offbyone.la:42140 auth1.offbyone.lan:ldap ESTABLISHED tcp 0 0 lab46.offbyone.la:45645 irc.offbyone.lan:ircd ESTABLISHED tcp 0 0 lab46.offbyone.la:58347 vm31.student.lab:ssh ESTABLISHED tcp 0 0 lab46.offbyone.la:44392 irc.offbyone.lan:ircd ESTABLISHED tcp 0 0 lab46.offbyone.la:51839 auth1.offbyone.lan:ldap ESTABLISHED tcp 0 0 lab46.offbyone.la:47426 irc.offbyone.lan:ircd ESTABLISHED tcp 0 0 lab46.offbyone.la:33595 auth1.offbyone.lan:ldap ESTABLISHED tcp 0 0 lab46.offbyone.la:44549 irc.offbyone.lan:ircd ESTABLISHED netstat -s |less Ip: 44800188 total packets received 2 with invalid addresses 280120 forwarded 0 incoming packets discarded 44488743 incoming packets delivered 58096734 requests sent out 7068 outgoing packets dropped Icmp: 10051 ICMP messages received 28 input ICMP message failed. ICMP input histogram: destination unreachable: 9389 echo requests: 250 echo replies: 412 9622 ICMP messages sent 0 ICMP messages failed ICMP output histogram: destination unreachable: 659 redirect: 7068 echo request: 1645 echo replies: 250 IcmpMsg: InType0: 412 InType3: 9389 InType8: 250 OutType0: 250 OutType3: 659 OutType5: 7068 OutType8: 1645 Tcp: 80063 active connections openings 38145 passive connection openings 26780 failed connection attempts 4252 connection resets received 85 connections established 44040550 segments received 57184990 segments send out 96026 segments retransmited 0 bad segments received. 30648 resets sent Udp: 388512 packets received
Demonstration of the chosen keyword.
If you wish to aid your definition with a code sample, you can do so by using a wiki code block, an example follows:
/* * Sample code block */ #include <stdio.h> int main() { return(0); }
Alternatively (or additionally), if you want to demonstrate something on the command-line, you can do so as follows:
lab46:~$ cd src lab46:~/src$ gcc -o hello hello.c lab46:~/src$ ./hello Hello, World! lab46:~/src$
source code is code written by a programmer in a text editor, object code is the source code compiled and ready to be linked to the binary code which is the binary executable the processor reads. library can be thought of as a place where header files are located.
lab46:~$ vi hello.c lab46:~$ file hello.c hello.c: ASCII C program text lab46:~$ gcc -c hello.c lab46:~$ ls hello.c hello.o lab46:~$ file hello.o hello.o: ELF 64-bit LSB relocatable, x86-64, version 1 (SYSV), not stripped lab46:~$ gcc -o helo hello.o lab46:~$ file helo helo: ELF 64-bit LSB executable, x86-64, version 1 (SYSV), dynamically linked (uses shared libs), for GNU/Linux 2.6.18, not stripped lab46:~$ file hello.o hello.o: ELF 64-bit LSB relocatable, x86-64, version 1 (SYSV), not stripped lab46:~$ file hello.c hello.c: ASCII C program text
students should be able to set permissions on file directories ad be able to filter text using utilities
the objective entails using reg expression cut(1),tr(1), and many more tools to filter text and be familiar with unix security.
Tell students to find what the default file and directory access is set to and how to change that default permission using umask and have an understanding of what is happening. ask students to search through a document and put the information into a useable manner by filtering the document or database. students should also be asked to change the permissions using chmod utility and demonstrate a clear understanding in permissions and security
lab46:~$ umask 0022 lab46:~$ touch file lab46:~$ ls -l file -rwxr-xr-x 1 rmatsch lab46 7481 Apr 21 16:21 file lab46:~$ umask 000 lab46:~$ touch file2 lab46:~$ ls -l file2 -rw-rw-rw- 1 rmatsch lab46 0 Apr 21 16:21 file2 lab46:~$ umask 22 lab46:~$ mkdir newd lab46:~$ ls -ld drwx-----x 30 rmatsch lab46 4096 Apr 21 16:23 . lab46:~$ ls -ld newd drwxr-xr-x 2 rmatsch lab46 6 Apr 21 16:23 newd lab46:~$ umask 22 lab46:~$ chmd -bash: chmd: command not found lab46:~$ chmod 777 newd lab46:~$ ls -ld newd drwxrwxrwx 2 rmatsch lab46 6 Apr 21 16:23 newd lab46:~$
1 is execute read is 4 and write is 2
Reflect upon your results of the measurement to ascertain your achievement of the particular course objective.