Linux Interview

What command can be used to findout server architechure (x86 or x64) apart from uname? •

arch

How do u findout the users who are NOT o!!ed in for more than "# da$s? which fie u wi chec%? •

ast & asto!& 'var'o!'wtmp 'var'o!'wtmp

When u tr$ to create a fie& u !ot a error that No space avaiabe* +ut actua$ space avaiabe on voume? How do u resove this issue? •

Tr$ this df ,i ,i ist inode information information instead of of boc% usa!e -.erhaps -.erhaps are $ou out of inodes on this fie s$stem*/& To rectif$ it& remove unwanted fies or move them somewhere ese*/

How do u extend the 01 in 0inux?

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2irst chec% whether is there free space avaiabe in the 13 where the 01 resides*  v!dispa$ or 

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 v!s

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Now& extend the 01 usin! beow command5 0 option to specif$ the sie to be increased*

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 vextend ,0 73 'dev'v!##'v#9 'dev'v!##'v#9

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2ina$& extend the 2ie s$stem space5  resie:fs 'dev'v!##'v#9

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What are the fieds in the 'etc'passwd fie* ;xpain them? •

There are < fieds in 'etc'passwd5

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=username5x5>@53@5comment5h =username5x5>@53@5comment5home ome director$5sheA

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>sername

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.assword

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>@

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.rimar$ !roup @

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Bomment description

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Home director$

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path Che assi!ned to the user 

What command can $ou use to review boot messa!es? •

The dmes! command can be used to dispa$ the s$stem messa!es durin! boot time*

Which account is created on 0inux instaation?

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With the instaation of 0inux& a super user account is created caed as DrootE*

What is a she? •

 F she is an interactive user interface to an operatin! s$stem services that aows an user to enter commands as character strin!s or throu!h a !raphica user interface* The she converts them to s$stem cas to the OC or for%s off a process to execute the command* C$stem ca resuts and other information from the OC are presented to the user throu!h an interactive interface* Bommon$ used shes are sh&csh&%s etc*

Which daemon trac%s events on $our s$stem? •

The s$so!d daemon trac%s the s$stem information and saves it to specified o! fies*

Gou are o!!ed on as a re!uar user* W ithout o!!in! off and o!!in! on as root& $ou are reuired to create a new user account immediate$* How woud $ou do it? •

This can be achieved b$ issuin! the su command* This wi prompt $ou for the password of the root account* .rovidin! the password& o!s $ou in as root* Now& $ou can perform an$ administrative duties* *

Gou are reuired to restore the fie memo*ben* t was bac%ed up in the tar fie I$+ac%up*tar* Which command woud $ou use to do it? •

The command that we woud use is5 tar ,xf I$+ac%up*tar memo*ben* t uses the x switch to extract a fie*

What is an NO@;? •

t is a structure which has the description of a the fies and pointers to the data boc%s of fie stored in it*The information contained is fie,sie& access and modification time& permission and so on*

What is 00O? •

00O is 0inux 0oader is a boot oader for 0inux* t is used to oad 0inux into the memor$ and start the Operatin! s$stem*******

What is the difference between home director$ and wor%in! director$? •

Home director$ is the defaut wor%in! director$ when a user o!s in* On the other hand& wor%in! director$ is the userEs current director$*******

What is N2C? What is its purpose? •

N2C is Networ% 2ie s$stem* t is a fie s$stem used for sharin! of fies over a networ%*******

How do  send emai with inux? •

;mai can be sent in 0inux usin! the mai command* ******

What is ;xpain J.I (Jed Hat .ac%a!e Iana!er) features*

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J.I (Jed Hat .ac%a!e Iana!er ) is a pac%a!e mana!ement s$stem (coection of toos to mana!e software pac%a!es)* Gou can use rpm to insta inux pac%a!es

 What is 0inux Che? What is Che Ccript? •

0inux she is a user interface used for executin! the commands* Che is a pro!ram the user******

What are .ipes •

 F pipe is a chain of processes so that output of one process (stdout) is fed an input (stdin) to another** ;xampe* ps Kef L !rep orace to ist orace process from process tabe*

What does nsoo%up do? •

Nsoo%up is used to find detais reated to a @omain name server* @etais i%e . addresses of a machine& IM records&* Fnd such****

What is +ash Che? •

+ash is a free she for >NM* t is the defaut she for most >NM s$stems* t has a combination of the B and orn she features* ******

How does the inux fie s$stem wor%? •

0inux fie structure is a tree i%e structure* t starts from the root director$& represented b$ '& and then expands into sub,directories*******

What is the name and path of the main s$stem o!? •

+$ defaut the main s$stem o! is 'var'o!'messa!es* This fie contains a the messa!es and the script written b$ the user* +$ d efaut a scripts are saved in this fie* This is the standard s$stem o! fie& which contains messa!es from a s$stem software& non,%erne boot issues& and messa!es that !o to dmes!* dmes! is a s$stem fie that is written upon s$stem boot*

What is the minimum number of partitions $ou need to insta 0inux? •

Iinimum : partitions are needed for instain! 0inux* The one is ' or root which contains a the fies and the other is swap* 0inux fie s$stem is function specific which means that fies and foders are or!anied accordin! to their functionait$* 2or exampe& a executabes are in one foder& a devices in another& a ibraries in another and so on* ' or DrootE is the base of this fie s$stem* F the other foders are under this one* ' can be consider as B5 *Cwap is a partition that wi be used as virtua memor$* f there is no more avaiabe JFI a 0inux computer wi use an area of the hard dis%& caed swap& to temporari$ store data* n other words it is a wa$ of expandin! $our computers JFI*

Which command is used to review boot messa!es? •

dmes! command is used to review boot messa!es* This command wi dispa$ s$stem messa!es contained in the %erne rin! buffer* We can use this command immediate$ after bootin! to see boot messa!es* F rin! buffer is a buffer of fixed sie for which an$ new data added to it

overwrites the odest data in it nvo%in! dmes! without an$ of its options causes it to write a the %erne messa!es to standard output* This usua$ produces far too man$ ines to fit into the dispa$ screen a at once& and thus on$ the fina messa!es are visibe* However& the output can be redirected to the ess command throu!h the use of a pipe& thereb$ aowin! the startup messa!es to be viewed on one screen at a time Which utiit$ is used to ma%e automate rotation of a o!? •

o!rotate command is used to ma%e automate rotation of o!*t aows automatic rotation& compression& remova& and maiin! of o! fies* This command is main$ used for rotatin! and compressin! o! fies* This Pob is done ever$ da$ when a o! fie becomes too ar!e*

What are the fieds in the'etc'passwd fie? •

t contains a the information of the users who o! into the s$stem* t contains a ist of the s$stems accounts& !ivin! for each account some usefu information i%e user @& !roup @& home director$& she& etc* t shoud have !enera read permission as man$ utiities& i%e s use it to map user @s to user names& but write access on$ for the superuser (root)* The main fieds of 'etc'passwd fie are5 9* >sername5 t is used when user o!s in* t shoud be between 9 and ": characters in en!th* :* .assword5 Fn x character indicates that encr$pted password is stored in 'etc'shadow fie* "* >ser @ (>@)5 ;ach user must be assi!ned a user @ (>@)* >@ # (ero) is reserved for root and >@s 9,QQ are reserved for other predefined accounts* 2urther >@ 9##,QQQ are reserved b$ s$stem for administrative and s$stem accounts'!roups* 4* 3roup @ (3@)5 The primar$ !roup @ (stored in 'etc'!roup fie) * >ser @ nfo5 The comment fied* t aow $ou to add extra information about the users such as users fu name& phone number etc* This fied use b$ fin!er command* 6* Home director$5 The absoute path to the director$ the user wi be in when the$ o! in* f this director$ does not exists then users director$ becomes ' <* Bommand'she5 The absoute path of a command or she ('bin'bash)* T$pica$& this is a she*

Which commands are used to set a processor,intensive Pob to use ess B.> time? •

nice command is used for chan!in! priorit$ of the Pobs* Jan!e of priorit$ !oes from ,:# (hi!hest priorit$) to 9Q (owest)*.riorit$ is !iven to a Pob so that the most important Pob is executed first b$ the %erne and then the other east important Pobs* This ta%es ess B.> times as the Pobs are schedued and are !iven priorities so the B.> executes fast* The priorit$ is !iven b$ numbers i%e ,:# describe the hi!hest priorit$ and 9Q describe the east priorit$*

* How do $ou create a new user account?

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useradd command is used for creatin! a new user account*

Which versions of 0inux have $ou wor%ed on ?

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Jedhat ;nterprise 0inux 4& and 6*