Linux Basic Course Ionrivera

7/25/2019 Linux Basic Course Ionrivera

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Copyright 2012 Hewlett-Packard Development Company, L.P. he in!ormation contained herein i" "#$%ect to change witho#t notice.

LINUX Basic Course&apoleon 'ivera

(L) - DC* )&+


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Introduction

What is Linux?

The Story of Linux.

How Linux is Built?


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Linux Basic Course

Part 1 - S Installation !H"LPart 2 - Basic Co##andsPart - User and $rou%

&d#inistrationPart - Linux 'ilesyste#( 'iles and)irectoriesPart / - Hel% Utilities( User*asswordPart - SudoPart - 'ile *er#issions and &ccess

Part - &CL


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*art -4* +n"tallation 'H5L


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Copyright 2012 Hewlett-Packard Development Company, L.P. he in!ormation contained herein i" "#$%ect to change witho#t notice./

S Installation

Prere6#i"ite7

1. 8mware 9ork"tation 8er"ion .0

2. 'H5L:.2i i"o

. (vaila$le di"k "pace 2/; - root directory.> - c#rrent directory.>command:name

- run a command in the current directory when the currentdirectory is not on the path..> - parent directoryM - home directory


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*athna#es

&/solute *athna#es($"ol#te i" typing the complete pathname G> i" there!erenceKionrivera"and$o@NO cd >etc>y#mKionrivera"and$o@NO

Brin,s you to the 7etc7yu# folder

!elati2e *athna#es 8.79Kionrivera"and$o@NO l"pl#gincon!.d y#m-#pdate"d.con!Kionrivera"and$o@NO cd .>pl#gincon!.d

he ..A - will go one level #p in the Ile "y"tem


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'ile 2iewin, and #ani%ulation

Co##and )escri%tion

#+dir =ake" a directory1le Determine" Ile type

2iew Di"play" the content o! the Ile

cat to concatenate or type the content o! the Ile on "creen

touch Change" Ile time"tamp"

c% Copie" Ile" or directorie"

#2 =ove" Ile" or directorie". +t i" al"o #"ed a" renaming tool.

r# Delete" Ile" or directorie"

r#dir Delete" an empty directory

ln =ake" a link or pointer


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*art :)"er and ;ro#p

(dmini"tration


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wo =ethod"71. ;raphical )"er =anager ool2. Commandline ool

&dd a New User


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Copyright 2012 Hewlett-Packard Development Company, L.P. he in!ormation contained herein i" "#$%ect to change witho#t notice.3

&dd a New User


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&dd a New User

(dd new #"er" !rom the command-line. *tart a terminal window"e""ion GApplications -> Accessories -> Terminal and at thecommand prompt enter a command "imilar to the !ollowing7

useradd ;# user0na#e< useradd ;# ionri2era

di i h i f


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he propertie" o! a #"er may $e changed #"ing the "ame )"er

=anager tool #"ed to add a #"er a" o#tlined a$ove.. 9ork thro#gh thevario#" "creen" in the )"er Propertie" dialog !or the "elected #"er andclick on the 4B $#tton to apply the change".

"ditin, the *ro%erties of a User

) l i U


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*elect the #"er to $e deleted and click on Delete. ( conIrmationdialog will appear providing the option to delete the #"erJ" homedirectory and temporary Ile". +! yo# wi"h to proceed, click onDelete.( #"er acco#nt may al"o $e deleted !rom command-line #"ing theuserdel#tility7

)eletin, User

+t i" al"o po""i$le to remove the #"erJ" home directory andmail "pool a" part o! the deletion proce""7

userdel user0na#e

userdel 3r user0na#e

&ddi $


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&ddin, new $rou%

&ew gro#p" are added either #"ing the )"er =anager graphical tool, or$y #"ing the gro#padd command-line tool.

U * i t $


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Lin#@ #"e" a user private groupG UPG "cheme, which make" )&+gro#p" ea"ier to manage. ( #"er private gro#p i" created whenever anew #"er i" added to the "y"tem.+t ha" the "ame name a" the #"er !or which it wa" created and that#"er i" the only mem$er o! the #"er private gro#p.

User *ri2ate $rou%

&ddi $


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o add a gro#p !rom the command line, #"e the gro#padd#tility.

&ddin, new $rou%

,rou%add ,rou%0na#e

%tion )escri%tion

3f( 33force 9hen #"ed with -ggidand gidalready e@i"t", gro#padd

will choo"e another #ni6#e gid!or the gro#p.

3,,id ;ro#p +D !or the gro#p, which m#"t $e #ni6#e and

greater than 33.

3=( 33+ey+ey>2alue 4verride >etc>login.de!"de!a#lt".

3o( 33non3uniue (llow to create gro#p" with d#plicate.

3%( 33%assword%assword )"e thi" encrypted pa""word !or the new gro#p.

3r Create a "y"tem gro#p with a ;+D le"" than /00.

5 dif i $


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5odifyin, $rou%

)"ing =anager tool to modi!y gro#p". *elect the Systemde"ktop men#Groups!rom theAdministration"#$-men# to la#nch the ;ro#p"

=anager tool.

5 dif i $


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o add an e@i"ting #"er to an e@i"ting gro#p !rom the command-line.

#"emod Q; gro#p:name1 #"er:name

o add an e@i"ting #"er to a n#m$er o! e@i"ting gro#p".

)"ermod Q; gro#p:name1:gro#p:name2,gro#p:name #"er:name

5odifyin, $rou%

) l ti $


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)eletin, $rou%

( gro#p may $e deleted !rom a "y"tem #"ing the gro#pdel#tility.

,rou%del ,rou%0na#e

&ote that i! the gro#p to $e deleted i" the primary gro#p !or any

#"er it cannot $e deleted. he #"er m#"t Ir"t $e deleted, ora""igned a new primary gro#p #"ing the #"ermod command7

user#od ;, user0na#e,rou%del ,rou%0na#e

*ass ord " %iration


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*assword "x%iration

o conIg#re pa""word e@piration !or a #"er !rom a "hell prompt, r#n the

!ollowing command a" root7

cha,eKoptionsN username

Force immediate pa""word e@piration $y r#nning the !ollowing commanda" root7

cha,e3d@username

*assword "x%iration


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Copyright 2012 Hewlett-Packard Development Company, L.P. he in!ormation contained herein i" "#$%ect to change witho#t notice./0

*assword "x%iration

%tion )escri%tion

3ddays *peciIe" the n#m$er o! day" "ince Xan#ary 1, 130the pa""word wa" changed.

3"date *peciIe" the date on which the acco#nt i" locked, in

the !ormat YYYY-==-DD. +n"tead o! the date, the

n#m$er o! day" "ince Xan#ary 1, 130 can al"o $e

#"ed.

3Idays *peciIe" the n#m$er o! inactive day" a!ter the

pa""word e@piration $e!ore locking the acco#nt. +!

the val#e i" 0, the acco#nt i" not locked a!ter thepa""word e@pire".

3l Li"t" c#rrent acco#nt aging "etting".

3#days *peci!y the minim#m n#m$er o! day" a!ter which the

#"er m#"t change pa""word". +! the val#e i" 0, the

pa""word doe" not e@pire.

35days *peci!y the ma@im#m n#m$er o! day" !or which the

pa""word i" valid. 9hen the n#m$er o! day"

"peciIed $y thi" option pl#" the n#m$er o! day"

"peciIed with the -doption i" le"" than the c#rrent

day, the #"er m#"t change pa""word" $e!ore #"ing

the acco#nt.

3Wdays

Shadow *assword


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Shadow *assword

+n environment" with m#ltiple #"er", it i" very important to #"e shadowpasswordsprovided $y the shadow-utilspackage to enhance the"ec#rity o! "y"tem a#thentication Ile". For thi" rea"on, the in"tallationprogram ena$le" "hadow pa""word" $y de!a#lt.

*hadow pa""word" improve "y"tem "ec#rity $y moving encryptedpa""word ha"he" !rom the world-reada$le 7etc7%asswdIle to7etc7shadow, which i" reada$le only $y the root#"er.

"to*hadow pa""word" re in!ormation a$o#t pa""word aging.*hadow pa""word" allow the >etc>login.de!" Ile to en!orce "ec#rity

policie".

Creatin, $rou%s )irectories


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*y"tem admini"trator" #"#ally create a gro#p !or each ma%or pro%ectand a""ign people to the gro#p when they need to acce"" that pro%ectJ"Ile".9ith thi" traditional "cheme, Ile managing i" diZc#lt[ when "omeonecreate" a Ile, it i" a""ociated with the primary gro#p to which they$elong. 9hen a "ingle per"on work" on m#ltiple pro%ect", it $ecome"

diZc#lt to a""ociate the right Ile" with the right gro#p. However, withthe )P; "cheme, gro#p" are a#tomatically a""igned to Ile" createdwithin a directory with the setgid$it "et. he "etgid $it make"managing gro#p pro%ect" that "hare a common directory very "imple$eca#"e any Ile" a #"er create" within the directory are owned $y thegro#p which own" the directory.



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Create the >var >mypro%ect directory $y typing the !ollowing at a "hellprompt7

#+dir 3% 72ar7#y%roAect

(dd the mypro%ect gro#p to the "y"tem7

,rou%add 72ar7#y%roAect

(""ociate the content" o! the >opt>mypro%ect> directory with themypro%ect gro#p7

chown root#y%roAect 72ar7#y%roAect

(llow #"er" to create Ile" within the directory, and "et the "etgid $it7

ch#od D 72ar7#y%roAect

(t thi" point, all mem$er" o! the #y%roAectgro#p can create and editIle" in the 72ar7#y%roAect7directory witho#t the admini"trator

having to change Ile permi""ion" every time #"er" write new Ile".

Users $rou%s tools and co##ands


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Users $rou%s tools and co##ands

gro#padd ( command to add gro#p".

grpck ( command to veri!y the >etc>gro#p Ile.gro#pdel ( command to remove gro#p".gro#pmod ( command to modi!y gro#p mem$er"hip.pwck ( command to veri!y the >etc>pa""wd and>etc>"hadow Ile".pwconv ( tool to convert "tandard pa""word" to"hadow pa""word".pw#nconv ( tool to convert "hadow pa""word" to "tandardpa""word".#"eradd ( command to add #"er".#"erdel ( command to remove #"er".

#"ermod ( command to modi!y #"er"

User and $rou%s 'iles


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Copyright 2012 Hewlett-Packard Development Company, L.P. he in!ormation contained herein i" "#$%ect to change witho#t notice.//

User and $rou%s 'iles

>etc>pa""wd )"er acco#nt in!ormation.>etc>"hadow *ec#re #"er acco#nt in!ormation.>etc>gro#p ;ro#p acco#nt in!ormation.>etc>g"hadow *ec#re gro#p acco#nt in!ormation.>etc>de!a#lt>#"eradd De!a#lt val#e" !or acco#nt creation.

>etc>"kel> Directory containing de!a#lt Ile".>etc>login.de!" *hadow pa""word "#ite conIg#ration.

Standard Users List


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Standard Users List

User UI) $I)

Ho#e

)irectory Shell *ac+a,esroot 0 0 >root >$in>$a"h "et#p

/in 1 1 >$in >"$in>nologin "et#p

dae#on 2 2 >"$in >"$in>nologin "et#p

sys - - - "et#p

ad# >var>adm >$in>$a"h "et#p

tty - / - - "et#p

dis+ - - - "et#p

l% >var>"pool>lpd >"$in>nologin "et#p#e# - - - "et#p

+#e# - 3 - - "et#p

wheel - 10 - - "et#p

cdro# - 11 - - #dev,=(B5D58

sync / G0 >"$in >$in>"ync "et#p

shutdown G0 >"$in >"$in>"h#tdown "et#p

halt G0 >"$in >"$in>halt "et#p

#ail 12 >var>"pool>mail >"$in>nologin "et#p

news 3 1 >var>"pool>new" >"$in>nologin "et#p

uuc% 10 1 >var>"pool>##cp >"$in>nologin "et#p

o%erator 11 G0 >root >"$in>nologin "et#p

Standard $rou%s


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Standard $rou%s

$rou% $I) 5e#/ersroot 0 root

/in 1 root, $in, daemondae#on 2 root, $in, daemon

sys root, $in, adm

ad# root, adm, daemon

tty /

dis+ root

l% daemon, lp

#e#

+#e# 3

wheel 10 root

#ail 12 mail, po"tI@

uuc% 1 ##cp

#an 1/

,a#es 20

,o%her 0

2ideo 3

di% 0

ft% /0

loc+ /


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*art E

Lin#@ File"y"tem",File" and Directorie"


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The 7etc7fsta/ 1le


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F"ta$ i" a Ile that contain" the in!ormation a$o#t the Ile"y"tem" thatwill $e mo#nted in the "y"tem.

5@ample content7

[root@localhost root]# cat /etc/fstab

\ device name mo#nt point !"-type option" d#mp-!re6 pa""-

n#m>dev>mapper> > e@t de!a#lt" 0 1L($oot >$oot e@t de!a#lt" 0 2none >dev>pt" devpt" gid/,mode20 0 0L(home >home e@t de!a#lt" 0 2none >proc proc de!a#lt" 0 0

none >dev>"hm tmp!" de!a#lt" 0 0>dev>hda "wap "wap de!a#lt" 0 0

The 7etc7fsta/ 1le

The 7etc7fsta/ 1le


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Device &ame - Ile"y"tem partition it"el! or data "o#rce.

=o#nt Point - where the data i" to $e attached to theIle"y"tem.

File"y"tem ype- Ile"y"tem type "#ch a" e@t2, e@t, etc.

4ption" - mo#nt option" to $e #"ed.

D#mp-!re6 - ad%#"t" the archiving "ched#le !or the partition.&ormally "et to

0 Gdi"a$le "ince d#mp $ack#p i"nEt #"ed.

Pa""-n#m - control" the order in which !"ck check" the device

!or error" at $oot time. he root device "ho#ld$e 1. 4ther partition" "ho#ld $e either 2 Gtocheck a!ter root or 0 Gto di"a$le checking !or thepartition altogether.

The 7etc7fsta/ 1le

The 7etc7fsta/ 1le


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Commonly #"ed mo#nt option"7

de!a#lt" mo#nt the Ile"y"tem with the de!a#lt "etting"7 rw, dev,e@ec, a#to, no#"er, a"ynca"ync all inp#t and o#tp#t to the Ile"y"tem will $e donea"ynchrono#"ly.

(n o$"olete mo#nting option "ince e@i"tence o! %o#rnallingIle"y"tem type"

a#to Ile"y"tem will $e mo#nted #pon $oot#p and with themo#nt -a commanddev interpret character or $lock device Ile" on the Ile"y"teme@ec permit e@ec#tion o! $inarie"noa#to Ile"y"tem can only $e mo#nted e@plicitly Gi.e. #"ing themo#nt command

no#"er do not allow ordinary #"er" to mo#nt the Ile"y"temro mo#nt the Ile"y"tem a" read-onlyrw mo#nt the Ile"y"tem a" read-write

The 7etc7fsta/ 1le

Co##on 'ilesyste# Ty%es


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Co##on 'ilesyste# Ty%es

ext 3 developed to overcome limitation o! the original e@tIle"y"tem. +t doe"nEt have %o#rnaling !eat#re

ext: 3 it allow" %o#rnalingextE 3 "#pport" h#ge individ#al Ile "ie and Ile"y"tem "ie.

+t can ena$le di"a$le %o#rnaling2fat 3 e@tended D4* Ile"ytemnfs 3 network Ile"y"tem #"ed to acce"" di"k" located onremote comp#ter"

s#/ 3 network Ile"y"tem that "#pport" the *=< protocol,#"ed $y 9indow" !or 9orkgro#p", 9indow" &, and Lan=anager

5ountin,7Un#ountin, of 'ilesyste#s


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5ountin,7Un#ountin, of 'ilesyste#s

o =o#nt7

O mo#nt Qt ]!"type^ ]device^ ]mo#nt point^

e.g. mo#nt Qt n!" >dev>"da3 >app"

o )nmo#nt7

O cd >O #mo#nt ]mo#nt point^

e.g. #mo#nt >app"

Note 5a+e sure you are not wor+in, on the current #ount

directory( otherwise( it would show an error Fde2ice /usyGwhile un#ountin,.

'ilesyste# Tools


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'ilesyste# Tools

#+fs

*ynta@7mkfs t !fstype>!device>

"#ample$mkfs -t e#t% &dev&sda'

fsc+*ynta@7

!"ck Qt ]!"type^ ]device^

5@ample7!"ck Qt e@t2 >dev>"da3

'ilesyste# Tools


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'ilesyste# Tools

tunefs*ynta@7

tune%fs c !numeric> -i !string> !device>

"#ample$tune%fs c (%) i *m &dev&sda'

9here7-c ma@im#m mo#nt co#nt-i interval $etween check"

o di"a$le check"7

tune%fs c -( i ) &dev&sda'

'iles and )irectories


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Linux Co##and Sy#/ols

5@ample7 sort ! +le(,t#t($ove, "ort" the content o! Ile1.t@t

5@ample7 cat Ile1.t@t Ile2.t@t

($ove e@ample, di"play" the content o! Ile1.t@t and redirect" it" o#tp#tto Ile2.t@t

5@ample7 cat Ile1.t@t ^ Ile2.t@t

hi" di"play" the content o! Ile1.t@t and redirect" to Ile2.t@t $y

in"erting it into ne@t line.

_5@ample7 p" Q!a@ _ grep ]"tring^_ wc Ql($ove e@ample, di"play" the o#tp#t o!ps $a"ed on target "tring andco#nt" it" line n#m$er. Command di"play" the o#tp#t o! the la"t

command wc -l



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'ile and )irectory 5ani%ulationo create a directory7 mkdir !directory>o remove a directory7 rm rf or rmdir]directory^ G#"e Qr! torec#r"ively and !orcea$ly remove a directory

o change directorie"7 cd !directoryname>o print c#rrent working directory7 pwdo Ind a Ile or a directory7 +nd !sourcedir> -name!directoryname&+lename>

Li"t content" o! a directory7 l" ]directory:name^l" Ql Gli"t" the long !ormat o! directoryin!ormationO l" -ldrw@r-@r-@ cli` #"er 102 X#n 1 0370 dir1-rw-r--r-- 1 cli` #"er 32 X#n 172 Ile1

S S S S S S S S S S S_ _ _ _ _ _ _ _ _ _ __ _ _ _ _ owner gro#p "ie date time name_ _ _ _ n#m$er o! link" to Ile or directory content"_ _ _ permi""ion" !or world_ _ permi""ion" !or mem$er" o! gro#p

_ permi""ion" !or owner o! Ile7 r read, w write, @ e@ec#te -no



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'ile and )irectory 5ani%ulationo create an empty Ile7 to#ch ]Ilenameô edit a Ile7 vi ]Ilenameô copy Ile" 7

cp +le( +le%cp +le/s0 dirname

o rename Ile" 7

G)ni@ doe" not rename, it move" !rom one Ilename to anothermv oldname newname

o move Ile" to a dièrent directory.mv +le directorymv +le/s0 directory

o remove Gdelete Ile"7rm +lenamerm +le( +le% ,, +le1rm -f +lename- !orced removal o! a Ilerm -i +lename- interactive 6#ery $e!ore removalrm -r +lename- rec#r"ive delete - dangero#".

rm -rf dir/s0 +le/s0- rec#r"ive !orce - C('5F)LRRR



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'ile and )irectory 5ani%ulation

Jiewin, 'iles without %enin,cat+lename- concatenate" and print. hi" will print o#t the content" o!the Ile to the "creen.

cat+le( ,, +le1- Concatenate and print. hi" will concatenate "everalIle" together and print to the "creen.

more+lename- di"play" Ile" one page G"creen at a time. Beep" oneline o! te@t !rom the previo#" "creen.

less +lename oppo"ite o! more, *crolling-#p and down i" it"advantage.

tail +lename o#tp#t" the la"t part o! the Ile.

tail f +lename o#tp#t" appended data o! a Ile in real-time a" the Ilegrow".

tail ()) +lename o#tp#t" la"t 100 line" o! the Ile.

*art : &cti2ity


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*art : &cti2ity

1. (dd a virt#al di"k into yo#r virt#al machine Ge.g. 2 ;< in "ie2. Format the di"k with Ile"y"tem type e@t

Command"7mkfs t e#t* !device>mkfs,e#t* !device>

. =o#nt the di"k with mo#ntpoint !ormat G>Ir"tname:la"tnameCommand7mount t e#t* !device> &+rstnamelastname

. )nmo#nt the Ile"y"tem. 'an !"ck to conIrm i! there areincon"i"tencie". (dd it into >etc>!"ta$ to a#tomatically mo#nt d#ring$oot-#p.Command7umount &+rstnamelastnamefsck,e#t* !device>

/. 'e$oot. File"y"tem "ho#ld $e a#tomatically mo#nted a!ter re$oot.. (!ter re$oot, create 2 directorie" #"ing name", ]Ir"tname^]la"tname^ into yo#r mo#nted directory.

. (!ter creating the directorie", create a Ile on each directory and p#ta content>data into it.


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*art D

Help )tilitie")"er Pa""word

Linux 5an *a,es


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#anSyntax

man K"ectionN command-name

Linux 5an *a,es

Settin, an account %assword


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%asswdSyntax

pa""wd K-optionN #"ername

%tions the can /e used

o lock the acco#nt

Syntax pa""wd Ql ]#"ername^

o #nlock the acco#nt

Syntax pa""wd Q# ]#"ername^

o view the pa""word "tat#" o! the acco#ntSyntax pa""wd Q* ]#"ername^

Se , a accou %ass o d

*assword &,in,


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5na$ling pa""word aging $y editing login.de!"

cat /etc/login.defs

, ,

*assword &,in,


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5dit the >etc>de!a#lt>#"eradd

he +&(C+85 "etting" indicatewhen to change the acco#nt toinactive a!ter the pa""word ha"e@pired

he 5P+'5 "etting can "et ane@plicit e@piration date !or all new#"er" in the !ormat YYYY-==-DD

&ote7

he a$ove mention "tep only a`ectnewly created #"er a!ter the"etting" ha" $een change. +n orderto #pdate e@i"ting #"er "ettingplea"e #"echage command.

, ,

*assword &,in,


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o #pdate the "etting" !or #"er"that already e@i"t, #"e the chagetool

chage -M 60 {username}

hi" will "et #"ernameP(**:=(:D(Y* "etting to 0 day"and #pdate the "hadow Ileaccordingly.

, ,

How to di"a$le pa""word aging !oran #"er acco#nt

o t#rn o` the pa""word e@piration!or an #"er acco#nt, "et the!ollowing7

-m 0 will "et the minim#mn#m$er o! day" $etween pa""word

change to 0

-= 33333 will "et the ma@im#mn#m$er o! day" $etween pa""wordchange to 33333

-+ -1 Gn#m$er min#" one will "etthe Pa""word inactiveA to never

-5 -1 Gn#m$er min#" one will "et(cco#nt e@pire"A to never.


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*art K*#do

SU)


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9hy we need to #"e "#do

- 5levate #"er privilege"- 5@ec#te command" !rom another #"er

-Logging Q log" "#do e@ec#ted command"

SU)


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How to execute sudo

sudo su -

sudo system-config-netor!

sudo reboot

SU)


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"dit 7etc7sudoers 1le

2i 7etc7sudoers-edit man#ally the >etc>"#doer" Ile

2isudo

- vi environment

- check" i! there "ynta@ error

*ample checking7

visudo

>>> /etc/sudoers: syntax error near line 22


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)e1nin, Co##and &liasCmnd_Alias ALIA_!A"# $ command% command2

#xam&les:

Cmnd_Alias '()WA*# $ /+in/r&m, /usr/+in/u&2date,

/usr/+in/yum

Cmnd_Alias L'CA)# $ /usr/+in/u&dated+

Cmnd_Alias "-C'""A!. $ /s+in/re+oot, /s+in/iconi0

SU)


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)e1nin, User &lias1ser_Alias ALIA_!A"# $ user%, user2

#xam&les:

user "AC3I!#$C'""A!.

1ser_Alias (1LL)I"#* $ millert, mi4e, dowdy

1ser_Alias 5A*)I"#* $ ed, edd, eddy

1ser_Alias 'L.)I"#* $ michael, 6ac4son

SU)


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)e1nin, !un as &lias*unas_Alias ALIA_!A"# $ user%, user2

#xam&les:

*unas_Alias '5 $ o&erator

*unas_Alias .7 $ orad+, sys+ase

SU)


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)e1nin, Host &lias3ost_Alias ALIA_!A"# $ host%, host2

#xam&les:

3ost_Alias 5A*C $ sun%8, s&arcstation%8

3ost_Alias LI!19 $ rhel, rhel;, rhel

3ost_Alias !( $ nssrv%, nssrv2

SU)


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)e1nin, 5ain *art1#* 3') $ =*1!A C'""A!.

1ser_Alias 3ost_Alias $ Cmnd_Alias !'5AW.:/5AW.:

#xam&les:

- ALL $ '()WA*#, L'CA)#, "-C'""A!.

(1LL)I"#* !( $ ='5 /+in/vi

SU)


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"xa#%le 7etc7sudoers 1le

"#doer".t@t


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*art

'ile *er#issionsand &ccess

'ile *er#issions and &ccess


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&ccess to 1les is de%endent on a users identi1cationand the %er#issions associated with a 1le.

Ty%es of &ccess

!ead1les contents can /e exa#ined

directories contents can /e exa#inedWrite1les contents can /e chan,eddirectories contents can /e chan,ed

"xecute1les 1les can /e used as a co##anddirectories can /eco#e current wor+in,

directory



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ch#od Change the Ile acce""

touch )pdate time"tamp on Ile or create a new Ileu#as+ Change de!a#lt Ile acce""chown Change the owner o! a Ilech,r% Change the gro#p o! a Ilesu *witch yo#r #"er identiIernew,r% *witch yo#r gro#p identiIer



92/120


ch#odQ Change Permi""ion o! a Ile

*ynta@7ch#od#ode0list 1leM Change permi""ion" o! the IleG"

Jalues

r 'ead permi""ion read Q w 9rite permi""ion write Q 2@ 5@ec#te permi""ion e@ec#te Q 1

"#ample$

chmod !1



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Sy#/olic5ethodSet 1

u = user

g = group

o = others

a = all

Set 2

+ = add

-= remove

= = set

Set 3

r =read

w = write

x = execute



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ctal 5ethod

rwxrwxrwx = complete file permission

rwx||rwx||rwx

3 sets of rwx:

Set 1 is the permission for user owner

Set 2 is the permission for the group ownerSet 3 is the permission for others



95/120

Copyright 2012 Hewlett-Packard Development Company, L.P. he in!ormation contained herein i" "#$%ect to change witho#t notice.3/

ctal 5ethod

Octal values:

R = w = 2 x = 1

!f a file has a permission of rwxr"xr"x# the octal valueof the permission is $$$$$$$$%



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)pdate time"tamp on Ile or create a new Ile

*ynta@7touch 3a#cO 1le M"#ample$

touch new1le

-a Change the acce"" time to time

-m Change the modi!y time to time-c +! the Ile doe" not e@i"t, do not create it

&ote7 to#ch command allow" yo# to create a new, empty Ile. +!the Ile already e@i"t", it will #pdate the time"tamp on the

Ile



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u#as+ 3 Permi""ion =a"k

*ynta@7

u#as+ 3SO #odeO

"#ample$#ma"k Q*#ma"k 02

&ote7 the ma"k that yo# de"ignate will only $e active inyo#r "e""ion, once yo# log o#t, it will revert $ack to thede!a#lt ma"k



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chown Change File 4wner"hip

*ynta@7chown owner ,rou%O 1lena#e M

"#ample$chown #"er2 >tmp>#"er2>!1

&ote7 4nly the owner o! a Ile Gor root can change theowner"hip o! the Ile



99/120


ch,r%

*ynta@7

ch,r% new,rou% 1lena#e

"#ample$chgrp "y" te"tIle

&ote7 4nly the owner o! a Ile Gor root can change the gro#pidentiIer a""ociated o! the Ile



100/120


ch,Creating a "harea$le directoryr%

*ynta@7

ch#od ,Prws testdir

5@ample7chgrp gro#p"hare te"tdir

1ote$ All users with the groupshare will 2e a2le towrite&change +les within the testdir directory



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suQ *witch )"er +D

*ynta@7su userna#eO"#ample$

"# ai3



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1. Change the Ile permi""ion o! myIle to make it rw-r-@r--2. )pdate the time"tamp o! te"tIle to the c#rrent time.. Change yo#r permi""ion ma"king in a way that when yo#e@ec#te #ma"k Q *, the re"#lt will $e #rw@,gr,or


103/120


*art &CL

&CL


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J"!JI"W

- 9hy (CL"- ype" o! (CL entrie"

- 5na$le (CL

- 8iewing (CL"

- (pplying (CL"

&CL


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Why &CLs

- 'ile owner control" permi""ion

- 9ant to give s%eci1c user or ,rou% a$ility toacce"" to 1les and directories

&CL


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Ty%es of &CL "ntries

"ntry ty%e Text for#

4wner #"er77rw#

&amed #"er #"er7name7rw#

4wning gro#p gro#p77rw#&amed gro#p gro#p7name7rw#

=a"k ma"k77rw#

4ther" other77rw#

&CL


107/120


"na/le acl on 1lesyste#

*et acl on Ile"y"tem

mount o acl /dev/ /

For per"i"tent conIg#ration"G"#rvive a re$oot

vi /etc/sta+

/dev/ / ext acl%

%

&CL


108/120


Jiew acl status 3 ,etfacl-)"er #tility to e@amine the (CL on a partic#lar Ile

- 5@amine" a IleE" inode to detemine whatpermi""ion" are "et

0etacl /

0etacl %2@txt

ile: %2@txt

owner: root

0rou&: rootuser::rwB

0rou&::rBB

other::rBB

&CL


109/120


Set &CL on 1le 7 directory 3 setfacl

- )"er command #tility to "et, modi!y, or delete (CL"on a Ile

- Can $e ran $y Ile owner or anyone given permi""ionto modi!y permi""ion"

setacl m u:root:rwx ileWhere:

Bm B modiy

u ty&e o acl=user

root name o the user

rwx ty&e o &ermission=read only,write and

execute

&CL


110/120


"xa#%les

setacl s u:alice:rx:i my(ile

setacl m o::drwx my(ile

setacl u my(ile

setacl d u:alice my(ile


111/120


*art QLinux Networ+in,

*in,


112/120


)"e" the +C=P protocolE" mandatory5CH4:'5b)5* datagram to elicitan +C=P 5CH4:'5*P4&*5 !rom a

ho"t or gateway.

\ping ]+P^

or\ping ]FbD&^

Traceroute


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rack" the ro#te packet" takeacro"" an +P network on their wayto a given ho"t. +t #tilie" the +P

protocolE" time to live GL Ieldand attempt" to elicit an +C=P+=5:555D5D repon"e" !rom each

gateway along the path to the ho"t

\tracero#te ]FbD&^

\tracero#te ]+P^ Ifcon1,


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+" #"ed to conIg#re the kernel-re"ident network inter!ace". +t i"#"ed at $oot time to "et #p the

inter!ace a" nece""ary. +! noarg#ment" are given, i!conIgdi"play" the "tat#" o! the c#rrently

active inter!ace". +! a "ingleinter!ace arg#ment i" given, itdi"play" the "tat#" o! the given

inter!ace only Ifcon1,


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\ i!conIgcheck the property o! a "inglenetwork inter!ace.

\i!conIg eth0

a""ign an ip on the y

\ i!conIg ]+P^ ]netma"k^

]device^ !oute


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=anip#late the kernelE" +P ro#tingta$le. +t" primary #"e i" to "et #p"tatic ro#te" to "peciIc ho"t" or

network" via an inter!ace a!ter itha" $een conIg#red with i!conIg

!oute


117/120


(dd" a ro#te to the network132./..@ via eth0A

\ ro#te add Qnet 132./..0netma"k 2//.2//.2//.0 dev eth0

check the c#rrently ro#ting ta$le

\ro#te -n

Netstat


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Print network connection", ro#tingta$le", inter!ace "tati"tic",ma"6#erade connection" and

m#ltica"t mem$er"hip

di"play all tcp connection" with it"

a""ociated program

\net"tat -tap

"thtool


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b#ery or control network driver andhardware "etting".

Check the inter!ace property.

\ ethtool ]device&ame^

Than+ you


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Documents

Linux Basic Course Ionrivera