UNIX Utilities and Shell Programming Part1

8/11/2019 UNIX Utilities and Shell Programming Part1

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C O N F I D E N T I A L

UNIX Utilities and ShellProgramming

Brian M. Appold

Director of Design Solutions

US Office Sunnyvale, CAOctober 2!


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C O N F I D E N T I A L 2October 2!

Co"rse Sched"le

" U#$% Utilities

" &ednesday, October '(, )*''a+

" riday, October '-, )*''a+" uesday, October 2', 2*/p+

" C S0ell 1rogra++ing

" &ednesday, October 22, 2*/p+


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C O N F I D E N T I A L !October 2!

Co"rse #oals

" U#$% co++ands" Use wcco++and to count c0aracters, ords, 3 lines" Use sortco++and to sort files" Use findco++ands to locate files" Use grep/egrepco++ands to select lines of a file

" Use sedco++and to edit a file" Use awkco++and to create for+atted output fro+ a

structured file

" C S0ell co++ands" 4ead user inputs

" Update a file" 1erfor+ arit0+etic" 5ist file contents sorted" 5ist a file by user specified searc0 pattern


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C O N F I D E N T I A L /October 2!

UNIX Utilities

" wcco++and

" sortco++and

" findco++and

" S0ell +etac0aracters

" grep/egrepco++ands

" 4egular e6pression +etac0aracters

" sedco++and

" awkco++and


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C O N F I D E N T I A L (October 2!

UNIX Utilities E$ercises

" 76ercise ' wc, sort, 3 find

" 76ercise 2 S0ell Metac0aracters

"76ercise ! 4egular 76pression

" 76ercise / 4eg. 76pression Metac0aracters

" 76ercise ( sedCo++ands

" 76ercise 8 Multi*line sedCo++ands

" 76ercise - awkCo++ands

" 76ercise 9 More awk


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UNIX Utilities % wc" Synta6:

wc;options< filena+e

" Options:

*l count lines* count ords

=note: spaces and returns define >ord?@

*c count c0aracters


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C O N F I D E N T I A L -October 2!

UNIX Utilities % wc" 76a+ples:

c petc0ip

) '( /8 petc0ip

c l petc0ip

) petc0ip

c petc0ip

'( petc0ip

c c petc0ip

/8 petc0ip


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UNIX Utilities % sort" Synta6:

sort;options< ;s;*s


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C O N F I D E N T I A L )October 2!

UNIX Utilities % sort" 76a+ples:

sort t: petc0ip

Cory =Big Boy@:cat:DSE:!F'9F'))):(:red:S+it0:)(!(

red:ferret::'2F/F2':':Brian:Gennedy:/-'(/

5ucy:cat:D5E:(F2'F'))(:(:ran:Andres:)/9(2Maggy:dog:5ab Mi6:)F2!F2':'2:o+:Hones:)(''-

Milly:cat:DSE:'F2F22:!:Betty:S+it0:)/(!)

Otis:cat:DSE:'F2F22:!:Ben:Stiller:/9-!/

1retIel:dog:errier Mi6:)F!F'))8:(:5ena:Eatc0er:)/98

S0elby:dog:Jolden 4etriever:-F!F22:'2:Diane:5ee:9(82!Spuny:dog:Jer+an S0eppard:8F'(F2:-:Gi+:4eed:)/(!8

#ote': default is for starting field to sort

#ote 2: petc0ip file s0on in Appendi6 A


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C O N F I D E N T I A L 'October 2!


sort t: 8 - ( 8 petc0ip

5ucy:cat:D5E:(F2'F'))(:(:ran:Andres:)/9(2


Maggy:dog:5ab Mi6:)F2!F2':'2:o+:Hones:)(''-red:ferret::'2F/F2':':Brian:Gennedy:/-'(/

S0elby:dog:Jolden 4etriever:-F!F22:'2:Diane:5ee:9(82!

Spuny:dog:Jer+an S0eppard:8F'(F2:-:Gi+:4eed:)/(!8


Cory =Big Boy@:cat:DSE:!F'9F'))):(:red:S+it0:)(!(Otis:cat:DSE:'F2F22:!:Ben:Stiller:/9-!/

#ote: if first sort finds duplicate data, t0en data is sorted by ;( 8sort r t: ' petc0ip? ill give you t0e sa+e result


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C O N F I D E N T I A L '!October 2!


sort n t: - petc0ip








Cory =Big Boy@:cat:DSE:!F'9F'))):(:red:S+it0:)(!(Maggy:dog:5ab Mi6:)F2!F2':'2:o+:Hones:)(''-

#ote: #u+eric ', 2, !, ', 2, K

ASC$$ ', ', 2, 2, !, K


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C O N F I D E N T I A L '/October 2!

UNIX Utilities % find

" Synta6:

finddirectory ;ot0er options< ;output options?

a : *f a' petc0ip

Cory =Big Boy@ cat DSE !F'9F')))( red S+it0

Spuny dog Jer+an S0eppard 8F'(F2

- Gi+ 4eed

Maggy dog 5ab Mi6 )F2!F2'

'2 o+ Hones

K


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C O N F I D E N T I A L -(

October 2!

awk% C"rl/ 5races" `ou +ay include +ultiple co++ands inside t0e curly

braces. 1ut a carriage return after eac0 co++and, or elseseparate t0e co++ands it0 se+icolons.

Tprint [',[2,[!,[/

print [(,[8,[-print >?

Tprint [',[2,[!,[/W print [(,[8,[-W print >?

T

print [',[2,[!,[/print [(,[8,[-

print >?


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C O N F I D E N T I A L -8

October 2!

awk% Printing +et"rns ( Tabs" Use Vn to print a carriage return, and Vt to print a tab.

cat a2

Tprint [',[2,[!,[/ >Vn? [(,[8,[- >Vn?

a : *f a2 petc0ip

Cory =Big Boy@ cat DSE !F'9F')))( red S+it0

Spuny dog Jer+an S0eppard 8F'(F2

- Gi+ 4eed

Maggy dog 5ab Mi6 )F2!F2'

'2 o+ Hones

K


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C O N F I D E N T I A L --

October 2!

awk% Processing a S"bset o1

+oBs Using Strings" A subset of t0e ros of t0e files are processed by using astring searc0 before t0e curly braces.

" String alues

Fregular*e6pressionFfield Fregular*e6pressionF

^ Fregular*e6pressionF

field ^ Fregular e6pressionF

" Boolean alues

]] logical O4

33 logical A#D


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C O N F I D E N T I A L -9

October 2!


+oBs Using Strings" 76a+ples: a : QF5enaF Tprint [8,[-,[( petc0ip

5ena Eatc0er (

a : Q['FMillyF Tprint [',[2,[!,[/ petc0ip

Milly cat DSE 'F2F22

a : Q['F\MF 33 ['Fy[F Tprint [',[( petc0ipMaggy '2

Milly !


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C O N F I D E N T I A L -)

October 2!


+oBs Using N"meric 6al"es" A subset of t0e ros of t0e files are processed by using anu+eric searc0 before t0e curly braces.

" #u+eric alues

field value

field ^ value

field L value

field L value

field N value

field N value


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C O N F I D E N T I A L 9

October 2!


+oBs Using N"meric 6al"es" 76a+ples: a : Q[( N / Tprint [8,[-,[( petc0ip

Betty S+it0 !

Ben Stiller !

Brian Gennedy '

a : Q[( '2 Tprint [8,[-,[( petc0ip

o+ Hones '2

Diane 5ee '2

a : Q[( L ( 33 [( N ' Tprint [',[( petc0ip

Spuny -


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C O N F I D E N T I A L 9'

October 2!


+oBs Bith )"lti,le Searches cat a![2FcatF Tprint >VtBuy so+e cat food for > ['

[2FdogF Tprint >VtBuy so+e dog food for > ['

[2FferretF Tprint >VtBuy so+e ferret food for > ['

a : *f a! petc0ip

Buy so+e cat food for Cory =Big Boy@

Buy so+e dog food for Spuny

Buy so+e dog food for MaggyBuy so+e dog food for 1retIel

Buy so+e cat food for Milly

K


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October 2!

E$ercise @ %awk Commands

4efer to t0e file in Appendi6 C, rite an awkco++and to:

'. 1rint a list of parties contained in t0e file c0ecingAnser: a : QTprint [! c0ecing

2. 1rint a list of parties and ite+ nu+bers for ite+s rittenin ebruary

Anser: a : Q[2F\2VFF Tprint [!,[' c0ecing

!. 1rint t0e nu+bers for c0ecs ritten for +ore t0at ['Anser: a : Q['^F\;Dd


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C O N F I D E N T I A L 9!

October 2!

awk% 5E#IN ( END Sections" `ou +ay add a B7J$# or 7#D section to your awkscript

in order to process infor+ation before or after any rosare processed.

cat a/

B7J$# Tprint >1artyVtVtC0ec A+ount?['F\;*)Vt? [/

a : *f a/ c0ecing

1arty C0ec A+ount

A+er. 76press 2/!.Citiban isa '/.)9

1ac. Jas37lec.!).-

1acific Bell 8(.((


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C O N F I D E N T I A L 9/

October 2!

awk% 6ariables

" Any ord t0at is not a ey ord ill be considered avariable na+e by awk. awkdoes contain so+evariables t0at it eeps trac of auto+atically.

" awkariables

$57#AM7 na+e of t0e data file

S field separator, defaults to spaces

# nu+ber of fields in current record

#4 nu+ber of t0e current record =i.e. line Z@

OS output field separator, representedby a co++a in print state+ents, defaults

to a space


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C O N F I D E N T I A L 9(

October 2!

awk% 6ariables

" 76a+ples:

a : Q#4 L ! 33 #4 N ( Tprint [8,[- petc0ip

o+ Hones

5ena Eatc0erBetty S+it0

a : Q7#D Tprint >0ere are >#4? records in >$57#AM7 petc0ip

0ere are ) records in petc0ip


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October 2!

awk% 6ariables

" 76a+ples:

cat locost

B7J$# TS>:?WOS>K?

[( N / Tprint [8,[-,[(

a f locost petc0ip

BettyKS+it0K!

BenKStillerK!BrianKGennedyK'


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C O N F I D E N T I A L 9-

October 2!

awk% User De1ined 6ariables

" ariables can be user defined.

cat a8

B7J$# T

S>:?

total

['F\DF Ttotaltotal[/

['F\;*)Balance is: > total

a f a8 c0ecing

Balance is: '/'(./


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October 2!

awk% Arithmetic

" awkcan be used to perfor+ arit0+etic operations.

" Su++ary

* R F standard arit0+etic re+ainder

add '

** subtract '


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C O N F I D E N T I A L 9)

October 2!

awk% Standard Arithmetic

" Addition

ec0o '2 /(8-.( !((.(/! !/ ] a QTprint ['[!

!(('2.(/!

" Division and Multiplication

ec0o '2 /(8-.( !((.(/! !/ ] a QTprint ['F[!

.!!92!

ec0o '2 ./(8- !((.(/! .!/- ] a QTprint [2R[/

.'(9/-(


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C O N F I D E N T I A L )

October 2!

awk% +emainder Arithmetic

" 4e+ainder ec0o '2 /(8-.( !((.(/! !/ ] a QTprint [22

'.(

ec0o '2 /(8-.( !((.(/! !/ ] a QTprint ['2

ec0o '2 /(8-.( !((.(/! !/ ] a QTprint [/2

ec0o '2 /(8-.( !((.(/! !/ ] a QTprint [!2

.(/!


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C O N F I D E N T I A L )'

October 2!

awk% Add8S"btract & Arithmetic

" Add one or subtract one

ec0o '2 /(8-.( !((.(/! !/ ] a QTprint [/

!(

ec0o '2 /(8-.( !((.(/! !/ ] a QTprint [/

!/

ec0o '2 /(8-.( !((.(/! !/ ] a QTprint **[/

!!


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C O N F I D E N T I A L )2

October 2!

E$ercise ; %)oreawk

4eferring to t0e petc0ip file, rite an awkco++and to:'. Jive a total of all t0e +a6i+u+ a+ounts oners are

illing to pay for e+ergency servicesAnser:

B7J$# TS>:?

total

Ttotaltotal[(

7#D Tprint >otal for e+ergency service: > total2. &rite a co++and to +ultiply t0e nu+ber (8.)- by

(/.!.Anser: ec0o (8.)- (/.! ] a QTprint ['R[2


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C O N F I D E N T I A L )!

October 2!

E$ercise ; %)oreawk

!. 1rint a c0art of pet na+es, species, and id nu+bers.1ut 0eaders on t0e output data. 1rint a total

nu+ber of pets at t0e botto+ of t0e c0art.Anser:

B7J$# Tprint >#a+eVtVtSpeciesVt$D?Tprint ['?Vt??Vt?[2?Vt?[9

7#D Tprint >otal nu+ber of pets: >#4

/. 5ist lines (*'Anser: a : Q#4 L ( 33 #4 N ' Tprint [ petc0ip

(. 5ist ani+als 0ose oners are illing to pay L[',. on +edical costs.

Anser: a : Q[( L ' Tprint [' petc0ip


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C O N F I D E N T I A L )/

October 2!

awk% F"nctions

" awkco+es it0 so+e built*in functions. Eere are aselect fe:

" split taes a string and inserts its fields into an array

split=string, array, field*separator@

" substr e6tracts a set of c0aracters out of a string

substr=string, start*position, +a6*lengt0@

" lengt0 returns t0e nu+ber of c0aracters in a string

lengt0=string@


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C O N F I D E N T I A L )(

October 2!

awk% F"nctions

" 76a+ples:

Use substr to s0orten t0e data output

T

petna+e substr=[',',(@

print petna+e >Vt? [(


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October 2!

awk% F"nctions

" 76a+ples:

Use lengt0 to deter+ine t0e data output

$f =lengt0=['@ L (@T

petna+e substr=[',',(@

print petna+e >Vt? [(

else

Tprint [' >Vt? [(


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C O N F I D E N T I A L )-

October 2!

C Shell Programming" Uses of t0e C s0ell

" 4unning C s0ell scripts" 5ocal variables" Obtaining user input" uoting" Using s0ell variables in awkand sed"

C s0ell redirection input, output, 3 error +essages" 0e ifstate+ent" Co++and line input" C s0ell arit0+etic" 0e whileloop" 0e foreachloop

" 0e switchstate+ent" Jlobal variables" 0e breakand continuestate+ents" 76it status


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October 2!

C Shell E$ercises

" 76ercise ) &riting a Si+ple C S0ell Script

" 76ercise ' uoting

" 76ercise '' 4edirection

" 76ercise '2 rueFalse Operators

" 76ercise '! Co++and 5ine Argu+ents


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C O N F I D E N T I A L ))

October 2!

C Shell % Uses o1 the C Shell

" 0e C s0ell can be used as a co++and interpreteror a progra++ing language. $n t0is training, t0efocus is on t0e progra++ing aspects of t0e C s0ell.

" A co++and interpreter ls

file' file2 file!

" A progra++ing language cat firstscript

Z^ FbinFcs0

Z 0is is a co++ent7c0o >0is is +y first C s0ell script?

firstscript

0is is +y first C s0ell script


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C O N F I D E N T I A L '

October 2!

C Shell % +"nning C Shell

Scri,ts0ere are ! ays to run a C s0ell script:'. Use t0e source co++and. 0is runs t0e script

co++ands in t0e current s0ell. source +yscript

2. ype in t0e script na+e at t0e pro+pt. 0is starts upa sub*s0ell in 0ic0 to run t0e +yscript co++ands. +yscript

!. 1recede t0e script na+e it0 FbinFcs0. 0is startsup a sub*s0ell in 0ic0 to run +yscript co++ands.

FbinFcs0 +yscript

#ote: you +ust 0ave read 3 e6ecute per+issions to use tec0niue 2,

read per+ission to use tec0niue ' or !


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C O N F I D E N T I A L ''

October 2!

C Shell % Local 6ariables

" 5ocal variables:

" Created it0 t0e setco++and

" isible only to your current s0ell

" Use setco++and to see all local variables

" 76a+ples:

set abc >'2!?

ec0o [abc

'2!


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C O N F I D E N T I A L '2

October 2!


" 76a+ples:

set

cd ForingFtraining

0istory 20o+e Fe6portF0o+eF

noclobber

pat0 =FusrFbin usrFlocalFbin Fe6portF0o+eFbin .@

pro+pt s0ell FbinFcs0

abc '2!


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C O N F I D E N T I A L '!

October 2!


" $f t0ere is any roo+ for confusion, use curly bracesaround your variable na+e.

" 76a+ple: ec0o [Tabc/(8

'2!/(8


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C O N F I D E N T I A L '/

October 2!

C Shell % Obtaining User In,"t

" Obtaining user input interactively, 0ile t0e script isrunning.

cat +yscript

Z^ FbinFcs0ec0o n >$nput a value: >

set na+e [N

ec0o [na+e

+yscript

$nput a value: &2!? %3riting a Sim,le C

Shell Scri,t!. Eave your script ec0o t0e folloing to t0e user:

C0ecing

'. Add a c0ec or deposit2. 4e+ove a c0ec or deposit

!. Calculate Balance

C0oose an Option:

/. 4ead t0e users response into a variable.


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C O N F I D E N T I A L '-

October 2!

E$ercise > %3riting a Sim,le C

Shell Scri,tAnser:Z^ FbinFcs0

Z Brian M. Appold

Z c0ecing.cs0

Z 0is script +anages a c0ecing account

Z 5ast updated: Oct '! 2!

ec0o >C0ecing?

ec0o >?

ec0o >'. Add a c0ec or deposit?

ec0o >2. 4e+ove a c0ec or deposit?

ec0o >!. Calculate Balance?ec0o >?

ec0o n >C0oose and Option: >

set c0oice [N


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October 2!

C Shell 0 "oting

" uoting

Q uotes everyt0ing e6cept

> uotes everyt0ing e6cept , , and [ run co++and first, insert output into

surrounding co++and

V uotes ne6t ' c0aracter =including @


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C O N F I D E N T I A L ')

October 2!

C Shell 0 "oting

" 76a+ples:

" Set*up variable

set var' >abc?

" Double uotes dont uote [, single uotes do

ec0o Q[var' [var'

ec0o >[var'? abc

" 0e bac uote c0aracter is different t0an singleuote c0aracter

ec0o date Sun #ov '2 22:!:!- 1S '))(


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C O N F I D E N T I A L ''

October 2!

C Shell 0 "oting

" #eit0er single or double uotes or on t0e ^C0aracter. Only t0e bacslas0 ill or.

ec0o 0ello^t0ere

t0ere: 7vent not found

ec0o >0ello^t0ere?

Un+atc0ed >.

ec0o Q0ello^t0ere

Un+atc0ed Q.

ec0o 0elloV^t0ere

0ello^t0ere


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C O N F I D E N T I A L '''

October 2!

C Shell 0 "oting

" Single and double uotes bot0 protect t0ebacslas0 c0aracter = V @.

ec0o Vvar' var' ec0o QV[var' V[var'

ec0o >V[var'? Vabc

C S S


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C O N F I D E N T I A L ''2

October 2!

C Shell % Using Shell 6ariables

in sedand awk" $n +ost cases, you can use a s0ell variable by ending yoursingle uoted string rig0t before t0e variable, t0en start it upagain rig0t after.

" 76a+ple: set lineno 2

a Q#4',#4Q[lineno Tprint [ petc0ip



sed n Q',[linenop petc0ip



C Sh ll U i Sh ll 6 i bl


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C O N F I D E N T I A L ''!

October 2!


in sedand awk" Eoever, if your variable is a string containing spaces,you +ust include double uotes around t0e variable.

" 76a+ple:

set na+e QBig Boy

a : QF?[na+e?F Tprint [ petc0ip


sed n QF?[na+e?Fp petc0ipCory =Big Boy@:cat:DSE:!F'9F'))):(:red:S+it0:)(!(

C Sh ll U i Sh ll 6 i bl


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C O N F I D E N T I A L ''/

October 2!


in sedand awk" or awk: $f your variable is a string containing spacesand you are inside a print state+ent, t0en synta6 is +oreco+ple6. $nclude one double uote rig0t before your firstsingle uoted string ends, and one rig0t after yoursecond single uoted string begins.

" 76a+ple:

set +ypet >òur ani+als na+e is >

a : QTprint >?[+ypet?? [' petc0ip

òur ani+als na+e is Cory =Big Boy@

òur ani+als na+e is SpunyK

#ote: t0is breas into ! pieces QTprint > >[+ypet? Q? ['


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C O N F I D E N T I A L ''(

October 2!

E$ercise & %"oting

'. &rite a sedco++and to list lines containing t0estring stored in t0e variable [petna+e.

Anser: sed n QF?[petna+e?Fp petc0ip

2. &rite an awkco++and to list t0e na+es of pets0ose +a6i+u+ e+ergency costs can e6ceed t0evalue stored in [+a6a+ount.

Anser: a : Q[( L?[+a6a+ount? Tprint [' petc0ip

C S


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C O N F I D E N T I A L ''8

October 2!

C Shell 0 +edirection

" 4edirecting outputL redirect output

L3 redirect output and errors

LL append

LL3 append output and errors

] pipe

" o prevent accidentally over*riting files it0

redirection, set noclobber. o over*ride noclobber,use an e6cla+ation point =^@L^ or L3^

C Sh ll + di ti


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C O N F I D E N T I A L''-

October 2!


" $f noclobber is set, t0e append sy+bol ill only appendto t0e end of an e6isting file. `ou need to use ane6cla+ation point if you ant it to create t0e file.

LL^

LL3^" Multiple co++and redirection

ls W date W 0o L outfile

=ls W date W 0o@ L outfile

=ls bananas L outfile@ L3 errfile" 4edirection input

N

C Sh ll + di ti


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C O N F I D E N T I A L''9

October 2!


" #ote: &0en t0e s0ell sees t0e redirection sy+bol =Lor L3@, t0e s0ell Ieros out t0e file being ritten to if ite6ists, or creates an e+pty file if it does not. òullnotice t0is 0en:

'. òur interrupt a progra+ it0 \C before any output isgenerated t0e e+pty file gets created

2. òu >sort abc L abc? 0e file abc is Ieroed out before

being sorted. òu inadvertently erase your file.

E i && + di ti


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C O N F I D E N T I A L'')

October 2!

E$ercise && %+edirection

Anser t0e folloing uestions for eac0 of t0ee6a+ples belo. &0at files are created by t0eco++and, and 0at infor+ation is stored in eac0 fileX

'. =ls L outfile8@ L3 outfile -Anser: outfile8 created, contains ls output

outfile- created, contains errors

2. ==ls W date W 0o@ L outfile9@ L3 outfile)Anser: outfile9 created, contains output of ls, date,

and 0o co++ands

outfile) created, contains errors

E i && + di ti


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C O N F I D E N T I A L'2

October 2!


!. &0at is t0e difference beteen t0e folloing 2co++andsX

ls L +ore

ls ] +oreAnser: 'st rites to file +ore

2nd pipe ls output to +ore

/. &0at ill 0appen if you run t0is co++andX

sort +yfile L^ +yfile

Anser: get an e+pty file, +yfile gets erased

E i && + di ti


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C O N F I D E N T I A L '2'

October 2!


(. &0y +ig0t you set up a co++and t0is ayX

=find F *na+e abc print L abc.out@ L3 FdevFnull

Anser: errors go to a >blac 0ole?

8. &0at does t0is co++and doX

=find F *na+e abc print L Qtty@ L3 FdevFnullAnser: output goes to tty =ter+inal nu+ber@

errors go to >blac 0ole?

C Sh ll Th if St t t


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October 2!

C Shell % The ifStatement

" Use an ifstate+ent to perfor+ an operation if avalue is >true?. or t0e C s0ell ifstate+ent, true+eans ' =i.e. non*Iero@ and false +eans .

" Synta6

if = [var '(@ t0en

ec0o >eurea?

endif

C Sh ll Th if St t t


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C O N F I D E N T I A L '2!

October 2!

C Shell % The ifStatement

if ='@ t0en

ec0o >t0is is true?

else

ec0o >t0is is false?endif

#ote:

then+ust be on t0e sa+e line as if, or else use a bacslas0 =V@`ou +ust include spaces around t0e trueFfalse operators suc0 as>>

C Sh ll Th it St t t


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C O N F I D E N T I A L '2/

October 2!

C Shell % The exitStatement

" o stop e6ecuting a script, use t0e exitstate+ent.

" Synta6

if = [anser >uit?@ t0en

e6it

endif

#ote: you can c0ec t0e e6it status using [status =i.e. ec0o[status@

C Sh ll T 8F l O t


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C O N F I D E N T I A L '2(

October 2!

C Shell % Tr"e8False O,erators

" #u+bers onlyL , L , N , and N

" #u+bers and strings

, ^" Strings

, ^

Set 6 >0i t0ere?

$f = >[6? 0iR @ t0en K.'. 0e ildcard c0aracters used 0ere are not regular e6pressions, t0ey

are t0e file na+e idcards used in co++ands suc0 as ls

2. Dont use uotation +ars around t0e 0iR 0ere

C Sh ll T 8F l O t


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October 2!

C Shell % Tr"e8False O,erators

" Co+binations33 logical A#D

]] logical O4

$f = [var 2( 33 [var2 L 2( @ t0en K

" ile attributes`ou can test a files attributes: r =read@, =rite@, 6=e6ecutable@, e =e6istence@, o =oners0ip@, I =Iero

lengt0@, f =plain file@, or d =directory@

$f = *r Ft+pF+yfile 33 *o Ft+pF+yfile @ t0en K.

C Shell 6ariables ( Constants


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C O N F I D E N T I A L '2-

October 2!

C Shell % 6ariables ( Constants

" `ou can get a trueFfalse value by testing a variable:

[Xvar rue if variable 0as a value

alse if variable 0as not yet been

assigned a value

[var rue if variable is not Iero, variable

+ust be a nu+ber

alse if variable is Iero or null7rror +essage if variable is not a

nu+ber



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October 2!


" 76a+ples:set var >a?

= [Xvar @ true

= [var @ synta6 error

= a @ synta6 error= >a? @ synta6 error

set var 9

= [Xvar @ true

= [var @ true= 9 @ true

= >9? @ true



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C O N F I D E N T I A L '2)

October 2!


" 76a+ples:set var

= [Xvar @ true

= [var @ false

= @ false= >? @ false

set var >?

= [Xvar @ true

= [var @ false= >? @ false

= @ false


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E$ercise &2 Tr"e8False


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C O N F I D E N T I A L '!'

October 2!

E$ercise &2 %Tr"e8False

O,erators!. =[Xvar'@Anser: rue

/. =[var'@

Anser: alse

(. =[Xvar!@

Anser: rue

8. =9(@

Anser: rue

-. =@

Anser: alse


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C Shell Command Line In,"t


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C O N F I D E N T I A L '!!

October 2!

C Shell % Command Line In,"t

" `ou can use variables ['*[) to access para+eterstyped after t0e script na+e

" [ 0olds t0e co++and na+e, [' 0olds t0e value of t0efirst argu+ent, and so on.

scriptna+e var' var2 var! var/

[ scriptna+e

[' var'

[2 var2

[! var!

[/ var/



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C O N F I D E N T I A L '!/

October 2!


" 76a+ple: cat +yscript

Z^ FbinFcs0

ec0o >your co++and as: [?

ec0o >your first para+eter as : ['?ec0o >all your para+eters ere: [R?

+yscript 0orray for captain spaulding

your co++and as: +yscript

your first para+eter as: 0orray

all your para+eters ere: 0orray for captain spaulding



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C O N F I D E N T I A L '!(

October 2!


" More variables associated it0 t0e co++and line:

[Zargv nu+ber of co++and line argu+ents

[R abbreviation for all para+eters

[argv sa+e as [

[argv;'< sa+e as ['K

[argv;)< sa+e as [)

[argv;'< note: not t0e sa+e as ['

[argv;''[' is odd?

endif

_var2 [2 2

if =[var2 @ t0en

ec0o >[2 is even?

else

ec0o >[2 is odd?

endif

set avg ec0o >scale2W=['[2@F2? ] bc

ec0o >0e average of t0e 2 nu+bers is [avg?

C Shell % The while Loo,


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C O N F I D E N T I A L '/'

October 2!

C Shell % The whileLoo,

" $f you ould lie a set of co++ands to e6ecuterepeatedly, you can use a whileloop.

" Synta6

set nu+ber '

0ile = [nu+ber N '8 @

ec0o [nu+ber

_ nu+ber

end

C Shell % The while Loo,


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C O N F I D E N T I A L '/2

October 2!

C Shell % The whileLoo,

" 76a+pleset badinput >true?0ile = >[badinput? >true? @

ec0o >7nter so+e input: >

set input [N

if = >[input? >?@ t0en Z user did not enter a value

set badinput >true?

ec0o >Bad input, try again?

ec0o >Eit return to continue?

set Pun [N Z pause t0e screen

clear Z clear t0e screen

else Z if user entered a valueset badinput >false?

endif

end


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C Shell % The switch Statement


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C O N F I D E N T I A L '//

October 2!

C Shell % The switchStatement

" So+eti+es youll need to test a value for+any different values. `ou can eit0er rite+any ifstate+ents, or you can use switch

state+ent instead.

C Shell % The switch Statement


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C O N F I D E N T I A L '/(

October 2!

C Shell % The switchStatement

" Synta6sitc0 =[userna+e@

case ;7e


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October 2!

C Shell #lobal 6ariables

" Created it0 t0e setenvco++and

" isible to your current s0ell and all your c0ildprocesses

" Use printenvor envto see all globalvariables

" Jlobal variables are auto+atically passed to

your scripts, local variables are not

C Shell % The PAT 6ariable


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C O N F I D E N T I A L '/-

October 2!

C Shell The PAT 6ariable

" 0e 1AE variable contains a list of directories to besearc0ed for co++ands typed at t0e pro+pt orincluded in your scripts. o ensure t0at yourco++ands ill be found 0en your script is run, you

can define t0e 1AE at t0e top of your script." Set using t0e global variable 1AE

setenv 1AE FusrFbin:Fbin:FusrFucb:.

setenv 1AE [T1AE:FusrFlocalFbin

" Set using t0e local variable pathset pat0 =FusrFbin Fbin FusrFucb .@

set pat0 =[pat0 FusrFlocalFbin@

C Shell % The break ( continue


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October 2!

C Shell The break( continue

Statements0e breakand continuestate+ents are used insidelooping structures suc0 as a whileloop. =0ey alsoor in a foreachloop@

" continue +oves you bac to t0e beginning oft0e 0ile loop

" break +oves you out past t0e 0ile loop

C Shell % The break ( continue


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C O N F I D E N T I A L '/)

October 2!

" 76a+ple:0ile = [var! ( @

ec0o >enter a value?

set anser [N

if =[Xanser@ t0en continue

else

if =[anser >uit?@ t0en

brea

endifK

end

C Shell The break( continue

Statements

C Shell % E$it Stat"s


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C O N F I D E N T I A L '(

October 2!

C Shell E$it Stat"s

U#$% co++ands 0ave an e6it status

" Access t0roug0 $status

" #ote: +ost U#$% co++ands ill return a

Iero if successful. 0is translates into afalse if you ant to use it in an ifstate+ent.

Ac4noBledgements


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C O N F I D E N T I A L '('

October 2!

Ac4noBledgements

" 1resentation adapted fro+ UC 76tensionclass entitled >Advanced U#$% Utilities andS0ell 1rogra++ing?, instructor Susan Barr

A,,endi$ A


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C O N F I D E N T I A L '(2

October 2!

A,,endi$ A

" 0e >petc0ip? file:Cory =Big Boy@:cat:DSE:!F'9F'))):(:red:S+it0:)(!(


Maggy:dog:5ab Mi6:)F2!F2':'2:o+:Hones:)(''-

1retIel:dog:errier Mi6:)F!F'))8:(:5ena:Eatc0er:)/98Milly:cat:DSE:'F2F22:!:Betty:S+it0:)/(!)





#ote:ile or+at petna+e:species:breed:DOB:vete6penseli+it:onerfna+e:onerlna+e:id

A,,endi$ 5


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C O N F I D E N T I A L '(!

October 2!

A,,endi$ 5" 0e >grepfile? file:

0is line contains a nu+ber: '2!/

0is line ends in an %

0is line ends in a dollar sign [

\ 0is line begins it0 a carat

0is line ends in a carat \Ei, +y na+e is Bob

Ei, +y na+e is Bib

Ei, +y na+e is Babs

0is is a date in t0e eig0ties :9F'!F9/:

0is is a date in t0e nineties :-F(F)2:Eere is an :A:

Eere are ! :AAA:s

Eere are ( :AAAAA:s

A,,endi$ C


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C O N F I D E N T I A L '(/

October 2!

A,,endi$ C

" 0e >c0ecing? file:

'':'F!F'))/:A+er. 76press:2/!.

'2:2F'F'))/:Citiban isa:'/.)9

'!:2F'2F'))/:1ac. Jas37lec.:!).-'/:2F'2F'))/:1acific Bell:8(.((

D2:2F'/F'))/:ABC $nc.:'/.

D':'F!F'))/:$4S:(/.

#ote: ile for+at c0ec nu+ber:date:na+e of party:a+ount


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UNIX Utilities and Shell Programming Part1

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Transcript of UNIX Utilities and Shell Programming Part1