[Centos 7] Shell Script 예제

ShellScript의 구문사용 하기 

# if ~ else

# vi ./if_test1.sh
#!/bin/bash
echo -n "Enter ls Command Path: "
read path

if [ -e $path ]; then
        echo "ls Command Execution file location: $path"
else
        echo "ls Command Execution file Not Found: $path"
fi

# chmod +x ./if_test1.sh

# ./if_test1.sh
Enter ls Command Path: /usr/bin/ls
ls Command Execution file location: /usr/bin/ls

# ./if_test1.sh
Enter ls Command Path: /bin/ls
ls Command Execution file location: /bin/ls

# ./if_test1.sh
Enter ls Command Path: /home/ls
ls Command Execution file Not Found: /home/ls

# vi ./if_test2.sh
#!/bin/bash
echo -n "Input Data: "
read a

if [ $a -gt 0 ]; then
        echo $a is 0 More
else
        echo $a in 0 Less
fi

# chmod +x ./if_test2.sh
# ./if_test2.sh
Input Data: 100
100 is 0 More
# ./if_test2.sh
Input Data: -10
-10 is 0 less

# vi ./if_test3.sh
#!/bin/bash
echo -n "Input Data: "
read data

if [ $data -ge 0 ]; then
        if [ `expr $data % 2` -eq 0 ]; then
                echo "Input Data Positive Even Number"
        else
                echo "Input Data Positive Odd Number"
        fi
else
        echo "Input Data Negative Number"
fi


# chmod +x ./if_test3.sh
# ./if_test3.sh
Input Data: 100
Input Data Positive Even Number

# ./if_test3.sh
Input Data: 99
Input Data Positive Odd Number

# ./if_test3.sh
Input Data: -10
Input Data Negative Number

# vi ./if_test4.sh
#!/bin/bash
echo -n "Input Your Kor Score: "
read kor

echo -n "Input Your Eng Score: "
read eng

echo -n "Input Your Mat Score: "
read mat

Sum=`expr $kor + $eng + $mat`
Avg=`expr $Sum / 3`

echo ""
echo Your Kor Score: $kor
echo Your Eng Score: $eng
echo Your mat Score: $mat
echo Your Total Score: $Sum
echo Your Average Socre: $Avg
echo ""

if [ $Avg -lt 70 ]; then
        echo "Your Average Score: $Avg Fail"
elif [ $kor -lt 60 ]; then
        echo "Your Kor Score: $kor Fail"
elif [ $eng -lt 60 ]; then
        echo "Your eng Score: $eng Fail"
elif [ $mat -lt 60 ]; then
        echo "Your mat Score: $mat Fail"
else
        echo "Congratulations on your passing the exam"
fi

# chmod +x ./if_test4.sh
# ./if_test4.sh
Input Your Kor Score: 70
Input Your Eng Score: 70
Input Your Mat Score: 70

Your Kor Score: 70
Your Eng Score: 70
Your mat Score: 70
Your Total Score: 210
Your Average Socre: 70

Congratulations on your passing the exam

#! /bin/bash
echo -n "생성할 계정명을 입력하시오 : "
read _new
echo -n " 생성할 계정이 $_new 가 맞습니까(y/n)? "
read _yes

if [ "$_yes" = Y -o "$_yes" = y ]
then
 useradd $_new
fi

# Case 

# vi ./case_test1.sh
# chmod +x ./case_test1.sh
#!/bin/bash
echo "Select Menu"
echo "1. Sum"
echo "2. Sub"
echo "3. Mul"
echo "4. Div"
echo -n "Choice Number Input: "
read choice
echo -n "Calc Data Input(2): "
read num1 num2

case $choice in
        "1" )
                echo "Sum Data: `expr $num1 + $num2`";;

        "2" )
                echo "Sub Data: `expr $num1 - $num2`";;

        "3" )
                echo "Mul Data: `expr $num1 \* $num2`";;

        "4" )
                echo "Div Data: `expr $num1 / $num2`";;

        * )
                echo "You made a wrong choice";;
esac

# ./case_test1.sh
Select Menu
1. Sum
2. Sub
3. Mul
4. Div
Choice Number Input: 1
Calc Data Input(2): 100 200
Sum Data: 300

# vi ./case_test2.sh
#!/bin/bash
if [ -z $1 ]; then
        rental="UnKnown Data"
else
        rental=$1
fi

case $rental in
        "car" )
                echo "$rental Rental Price: 40$";;
        "motorcycle" )
                echo "$rental Rental Price: 20$";;
        "bicycle" )
                echo "$rental Rental Price: 10$";;
        * )
                echo "$rental";;
esac

# chmod +x ./case_test2.sh
# ./case_test2.sh car
car Rental Price: 40$

# ./case_test2.sh motorcycle
motorcycle Rental Price: 20$

# ./case_test2.sh bicycle
bicycle Rental Price: 10$

# ./case_test2.sh
UnKnown Data

$ Select 

# vi ./select_test1.sh
#!/bin/bash
PS3="Please Enter Your Choice: "
option=("Coke" "Sprite" "Fanta")
select opt in "${option[@]}"
do
        case $opt in
                "Coke" )
                        echo "Coke Price 2000Won" ;;
                "Sprite" )
                        echo "Sprite Price 1800Won" ;;
                "Fanta" )
                        echo "Fanta Price 1500Won" ;;
                * )
                        break ;;
        esac
echo "Finished Any Key Enter"
done

# chmod +x ./select_test1.sh
# ./select_test1.sh
1) Coke
2) Sprite
3) Fanta
Please Enter Your Choice: 1
Coke Price 2000Won
Finished Any Key Enter
Please Enter Your Choice: 2
Sprite Price 1800Won
Finished Any Key Enter
Please Enter Your Choice: 3
Fanta Price 1500Won
Finished Any Key Enter
Please Enter Your Choice: 4
   - PS3 변수의 경우 select 문에서 사용 할 반복 메시지를 저장하는 용도로 사용 된다.
   - 이름은 반드시 PS3로 정의

$ For

# vi ./for_test1.sh
#!/bin/bash
lst='1 2 3 4 5 6 7 8 9 10'
for cnt in $lst
do
        echo -n $cnt
done
echo ""

# chmod +x ./for_test1.sh
# ./for_test1.sh
12345678910

# vi ./for_test1.sh
#!/bin/bash
for (( cnt=1;cnt<=10;cnt++ ))
do
        echo -n $cnt
done
echo ""
# ./for_test1.sh
12345678910

# vi ./for_test2.sh
#!/bin/bash
arr=(it codeing taehei)
for name in ${arr[@]}
do
        echo "$name"
done

[root@MyLinux ~]# chmod +x ./for_test2.sh
[root@MyLinux ~]# ./for_test2.sh
it
codeing
taehei

# vi ./for_test3.sh
#!/bin/bash
for file in $(ls /var/log/*.log)
do
        echo " ---- $file ---- "
        head -1 $file
        echo ""
done

# chmod +x ./for_test3.sh
# ./for_test3.sh
 ---- /var/log/Xorg.0.log ----
[    15.471]

 ---- /var/log/Xorg.9.log ----
[     8.932]

 ---- /var/log/boot.log ----
[  OK  ] Started Show Plymouth Boot Screen.

 ---- /var/log/vmware-vmsvc.log ----
[ 2월 19 10:29:08.256] [ message] [vmsvc] Log caching is enabled with maxCacheEntries=4096.

 ---- /var/log/vmware-vmusr.log ----
[ 2월 19 10:37:03.527] [ message] [vmusr] Log caching is enabled with maxCacheEntries=4096.

 ---- /var/log/wpa_supplicant.log ----
Successfully initialized wpa_supplicant

 ---- /var/log/yum.log ----
Feb 24 14:29:45 Updated: 1:quota-nls-4.01-19.el7.noarch

# vi ./for_test4.sh
#!/bin/bash
echo "---- Directory List ----"
echo -n "Input Path: "
read pat
for lst in $(ls $pat)
do
        echo $lst
done
# chmod +x ./for_test4.sh
# ./for_test4.sh
---- Directory List ----
Input Path: /home
taehei
user1

# vi ./for_test5.sh
#!/bin/bash
for num in {1..10..2}
do
        echo $num
done

# chmod +x ./for_test5.sh
# ./for_test5.sh
1
3
5
7
9

# vi ./for_test6.sh
#!/bin/bash
sum=0
for (( i=1;i<=10;i++ ))
do
        sum=`expr $sum + $i`
done
echo "$sum"

# chmod +x ./for_test6.sh
# ./for_test6.sh
55

# vi ./for_test7.sh
for i in 1 2 3 4 5 
do
	echo $1
done

# chmod +x ./for_test7.sh
# ./for_test7.sh
1
2
3
4
5

$ While

# vi ./while_test1.sh
#!/bin/bash
while [ -f /etc/passwd ]
do
        tail -5 /etc/passwd
        break
done

# chmod +x ./while_test1.sh
# ./while_test1.sh
avahi:x:70:70:Avahi mDNS/DNS-SD Stack:/var/run/avahi-daemon:/sbin/nologin
postfix:x:89:89::/var/spool/postfix:/sbin/nologin
ntp:x:38:38::/etc/ntp:/sbin/nologin
tcpdump:x:72:72::/:/sbin/nologin
itbank:x:1000:1000:itbank:/home/itbank:/bin/bash

# vi ./while_test2.sh
#!/bin/bash
echo -n "Your Password Input: "
read pass

while [ $pass != "1234" ]
do
        echo "Plz Enter again"
	echo -n "Your Password Input: "
        read pass
done
echo "Login Success"

# chmod +x ./while_test2.sh
# ./while_test2.sh
Your Password Input: 1234
Login Success

# ./while_test2.sh
Your Password Input: aaaa
Plz Enter again
Your Password Input: bbbb
Plz Enter again
Your Password Input: 1234
Login Success

[ 로컬 콘솔 터미널 창에서 실행 ]
# firefox 

[ Putty 터미널 창에서 스크립트 작성 ]
# vi ./while_test3.sh
#!/bin/bash
echo "==== Process Check! ===="
echo -n "Input Apps Name: "

while read apps
do
        if pidof $apps; then
                echo -n "Running PID $apps: "
                pidof $apps
        else
                echo "Not Running PID"
        fi

        echo -n "Exit(0), Continue(1): "
        read choice
        if [ $choice == 1 ]; then
                echo -n "Again Input Apps Name: "
        else
                echo "Scripts Finished!!"
                exit 0
        fi
done

# chmod +x ./while_test3.sh
# ./while_test3.sh
==== Process Check! ====
Input Apps Name: firefox
23225
Running PID firefox: 23225
Exit(0), Continue(1): 1

Again Input Apps Name: aaa
Not Running PID
Exit(0), Continue(1): 0
Scripts Finished!!

$ 사용자 정의함수

# vi ./function_test1.sh
#!/bin/bash
function Sum() {
        echo "Sum : `expr $num1 + $num2`"
}

echo -n "Enter First Number: "
read num1

echo -n "Enter Second Number: "
read num2

Sum
# ./function_test1.sh
Enter First Number: 100
Enter Second Number: 200
Sum : 300

 

# vi ./function_test2.sh
#!/bin/bash
function Result() {
        if [ $1 -eq "1" ]; then
                echo Check [ Ok ]
        else
                echo Check [ NO ]
        fi
}
echo -n "Input Data 1 or 0: "
read num
Result $num

# chmod +x ./function_test2.sh
# ./function_test2.sh
Input Data 1 or 0: 0
Check [ NO ]

# ./function_test2.sh
Input Data 1 or 0: 1
Check [ Ok ]

# vi ./function_test3.sh
#!/bin/bash
func1() {
        echo "Func1 is Return Function!!!"
        return 100
}

func1
return_val=$?
echo "Func1 Return Value: $return_val"

# chmod +x function_test3.sh
# ./function_test3.sh
Func1 is Return Function!!!
Func1 Return Value: 100

$ ETC

# vi ./eval.sh
#!/bin/bash
str1="uname -sr"
echo -n "Linux System Info: "
eval $str1

cmd_lst="ls /usr/bin | wc -l"
echo -n "Linux Command Count: "
eval $cmd_lst

if [ ! -z $1 ]; then
        proc_info="ps -ef | grep $1"
        eval $proc_info
else
        proc_info="Not Found Aguments"
        echo $proc_info
fi
# chmod +x ./eval.sh
# ./eval.sh bash
Linux System Info: Linux 3.10.0-514.el7.x86_64
Linux Command Count: 1587
root        731         1  0 12:39 ?          00:00:00 /bin/bash /usr/sbin/ksmtuned
root       2639   2633  0 12:40 pts/0    00:00:00 -bash
root       6612   6475  0 18:56 ?          00:00:00 /usr/bin/ssh-agent /bin/sh -c exec -l /bin/bash -c "env GNOME_SHELL_SESSION_MODE=classic gnome-session --session gnome-classic"
root       7174   7169  0 18:57 pts/1    00:00:00 bash
root       8536   2639  0 20:26 pts/0    00:00:00 /bin/bash ./eval.sh bash
root       8541   8536  0 20:26 pts/0    00:00:00 grep bash

[ 일반 사용자 계정 "USER"로 접속 후 작업 진행 ]
$ vi ./set_test.sh
#!/bin/bash
echo "Before Error"
cd /root
echo "After Error"
$ chmod +x ./set_test.sh
$ ./set_test.sh
Before Error
./set_test.sh: line 3: cd: /root: 허가 거부
After Error
   - 현재 Error가 발생하더라도 스크립트가 계속 실행되는 것을 확인 할 수 있다.
   - 스크립트는 중간에 Error가 발생 할 경우 더 이상 실행되지 않는것이 더 효과적이다.

$ vi ./set_test.sh
#!/bin/bash
set -e echo "Before Error"
cd /root
echo "After Error"
$ ./set_test.sh
./set_test.sh: line 3: cd: /root: 허가 거부
   - Error가 발생 할 경우 더 이상 스크립트가 실행되지 않는 것을 확인한다.
   - Error가 발생 할 것 같은 지점에 "set -e"를 활용한다.

# export MyVAR="Hello World"
# echo $MyVAR
Hello World
# unset MyVAR
# echo $MyVAR
   - Unset의 경우 주로 환경변수를 해제할 때 사용된다.

# vi ./command.sh
#!/bin/bash
echo "[ Shadow File 3 Line Check ]"
echo "$(head -3 /etc/shadow)"
echo "Today is $(date)"

# chmod +x ./command.sh
# ./command.sh
[ Shadow File 3 Line Check ]
root:$6$0/FFFZYZ3kpWzby.$56drrKqTK.pw0cAt9Re3EdMIwvTVqokQlg60::0:99999:7:::
bin:*:17110:0:99999:7:::
daemon:*:17110:0:99999:7:::
Today is 2020. 02. 28. (금) 19:40:09 KST