Lập trình SHELL trên Linux

Lập trình SHELL trên Linux




Giới thiệu Linux Shell
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 !"#$% &'()*)(+(, #/("0(1
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2(34&5 6 !%78, !9%7#, !%7:; !<%7=
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:;!,:( %  >0?,2(3
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 +(@? "#,A)( BC(&'D BC
Giới thiệu Linux Shell
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2(3,A+0E((D(1 ,> *,, F,!G( ,, %HI "
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6J*KLM NOKL OKO
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P,0
L  ("9Q* ,( ("!'-* R,B-SS %
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GTI+
U↵
Mục đích của shell
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P*7(@? " 0V()(HIW* "(4X70H(/("5QYZ "B
0V
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[><(.'()05(#/(\()(HI

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2BC

 4BV* "Z0+#(.C!0V](  (%

,(D "0(F^"57 _0V<EQ*4JR0(19(+`*
!(aS%7#_ >!a,Sb( %
Điều khiển shell
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 +0VHI&'D BC]( 'D 6*C0V#(.#'?
<c( ](  (
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6(*0+#(.C0(19(+ 
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G(.CZ_ "
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6+&* "#,&B-#QY (B-&C
Điều khiển shell từ dòng lệnh
GTId#(+?B-&(R\(e(!%fP#C "0+dZg 0HI ",0+
(+?P+0(19(+ 0&
$ for file in *
>do
> if [ $(grep –l ‘main()’ $file)]
> then
> more $file
> fi
>done
Điều khiển shell từ script
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V0(+^#("0(19(+ Z_ " 9 4 (95( "/00+H0E(#(& YD

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[+@<F,C+0* "#,&B-#QY 0]&(B-0+(
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GTI,g 
#!/bin/bash
for file in *
do
if [ $(grep –l ‘main()’ $file) ];
then
more $file
fi
done
Môi trường Shell
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h'()  4F*(. B(J,#("C0VT3*

,i
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6*B-9c(,
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6*<(.
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P("*j,*5]

k*<T
Ngôn ngữ lập trình shell
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[+,F,&C +HI<49lC,F,#m<F,!n#(77%
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6*Y<F^'D 

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64J (
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(. 9(+57\(75#<(.'()

[(19("9(+<(+R '(<o

64J0(19(+C(a77b( 7=
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;
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6* "&((!<( L(%
Cấu trúc shell script
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h& (<Fi
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p_0Y-Q),<(. 0VHI#](C'? (R!#TIqrS<(S<%
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6*JT<X0Y#/(4m!q%

6*__ ( * "^2(3,>*4J0(19(+7=

P( (
6
[>s13U,t3M (N
6 (USM (N
6UM (N
Lệnh ghi ra màn hình

6J*,KLuOK<(+RO

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p0+(+?(*?*<(.7<(+R,>\(C

P,0

P,v9'35_9((

L.<(+R \(0>,>*9A+HI*9w0><("x7x<7x7xy!9wz:66{ 
%7=
GTI
,|;,b,}~
,|6U•€•~
Lệnh vào ra

6J*M<(.NK<(.OK<(.O

p0+0]D ("Z<T

GTI (0]#(D ("
U#(#(
#!/bin/bash
#Vi du sử dụng lenh read va echo
echo “Nhap mot so: ”
read num
echo “So vua nhap la: $num”
Đặc điểm biến shell

(. D(*9(C ,AHI<(.9'Y9(<*,#0?‚9(+

h>0?74F*<(.010V9c(,#R?9(+\(!F9(*(*? &5C ƒ3 \(%


 #&#( "-"T`0&+<(.\(50+("Aj9(QY

(. +0+ BC,>0+0(19(+'()(.„<("D,)
Sử dụng biến

6ƒ'D BC7 4A*# 4(*?^<(.

MQ<(.N…M(*?Nc0„(*?+ &57\(Z&<(.9*

MQ<(.N…†,†k*(*?,<(. 9.sF("^& "

UMQ<(.N0+ 4(*??^<(.
GTI
K=Oq3…‡
K=Oq,U3
‡
Biến môi trường

8(C 9c(0&4ˆ&5<(.0V9(<*,#*(*?>0?7J0V]( <(.'()

6*<(.'())0V#(.,0+„<("#/(*<(.,)(0?‚

h\('()0mBR*<(.'()(Q<(",I0T(Q

[+(+?*<(.'() "#[+,&<(.'()/( "3,
Một số biến môi trường

;‰P:h€PQ*2(3


;‰h€PI^^)(

;€22 ("

ŠpPI("

:P;p**I0+d9(.* "7„*<c(4(4!%

•€•PQ)(("

P€•h8(+^( ("

p4X
Cách dùng các dấu bọc

P, (< ,(40><(",* "(C "*7w‚#*("
9*<("

6*4 

p41!†%

p4*0!e%

p4*9A!|%
Dấu huyền (`)

p0+](("& ""5, (

GTI7, (*_


(…†b†!,>(…U!b%%

(,…†bL Ug †

P,0

p_`(" "b#*0)‹("#,<(.(

p_(" "b0.5_,B-Ug #*,<(. (,

p0+](("& ""5, (

GTI7, (*_

(…†b†!,>(…U!b%%

(,…†bL Ug †

P,0

p_`(" "b#*0)‹("#,<(.(

p_(" "b0.5_,B-Ug #*,<(. (,
Dấu nháy đơn (‘) và nháy kép (“)

p0+(+?C<c( Q,,>*(*?,<(.\(

p4*9A!|%9((`("#/((*?^<(.4U


p4*0!e%9((`(Q_#m<F,„ "

GTI
…|Œ,P•
,•U|q{Œ,P
,fUfq{U
Các ký tự đặc biệt của Bash
Biến tự động

6_]( <(.Ž0]75#?T

6*<(.0V\Vˆ

PQ<(.0V,/

6y<(.0&UyU•
Uy6RQ^ "
6*<(.<X0YZU

.<(.#?T /•CHIJ*U•‘0+0V*(*?^J
GTIU•y‘
Tham biến vị trí đặc biệt

 <<(.#?T0><("

Uq5 V<(.#?T!9'jUy%

U’PF#14F*<(.#?T0V0/(3„!,(Uy%

U“p*4F*<(.7,(ZUy

Biểu thức toán học

6*,*Ht7L7“7S7”

HI 7U!!%%73,>UKO0+("j(*?<(+R,*]

GTI
•…•t|
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Biểu thức điều kiện
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Cấu trúc rẽ nhánh if-else
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