シェル学習ノート

#!/bin/bash 
echo "Hello World!"

#!/bin/bash 
myUrl="blog.csdn.net/charles1e"
myName="yanke"
echo ${myUrl}
echo ${myName}
myName="Yan Ke"
echo ${myName}

#!/bin/bash 
myUrl="www.blog.net/charles1e"
readonly myUrl
myUrl="www.blog.net/charles"

./ReadOnlyVariable.sh: line 5: myUrl: readonly variable

#!/bin/bash 
myName="Yan Ke"
unset myName
echo ${myName}

a=10
b=20
val=`expr $a + $b`
echo "a+b: ${val}"

val=`expr $a - $b`
echo "a-b: ${val}"

val=`expr $a \* $b`
echo "a*b: ${val}"

val=`expr $b / $a`
echo "b/a: ${val}"

val=`expr $b % $a`
echo "b%a: $val"

if [ $a == $b ]
then
    echo "a is equal to b"
fi

if [ $a != $b ]
then
    echo "a is not equal to b"
fi

#!/bin/bash 
a=10
b=20

if [ $a -eq $b ]
then
    echo "$a -eq $b : a is equal to b"
fi

if [ $a -ne $b ]
then
    echo "$a -ne $b : a is not equal to b"
fi

if [ $a -gt $b ]
then
    echo "$a -gt $b : a is greater than b"
else
    echo "$a -gt $b : a is not greater than b"
fi

if [ $a -lt $b ]
then
    echo "$a -lt $b : a is lese than b"
else
    echo "$a -lt $b : a is not less than b"
fi

if [ $a -ge $b ]
then
    echo "$a -ge $b : a is greater or equal to b"
else
    echo "$a -ge $b : a is not greater or equal to b"
fi

#!/bin/bash 
file="./helloworld.sh"

if [ -r $file ]
then
    echo "File has read access"
else
    echo "File does not have read access"
fi

if [ -w $file ]
then
    echo "File has write access"
else
    echo "File does not have write permission"
fi

if [ -x $file ]
then
    echo "File has execute permission"
else
    echo "File has no execute permission"
fi

if [ -f $file ]
then
    echo "File is an ordinary file"
else
    echo "This is a special file"
fi

if [ -d $file ]
then
    echo "File is a directory"
else
    echo "This ia not a directory"
fi

if [ -s $file ]
then
    echo "File size is zero"
else
    echo "File size is not zero"
fi

if [ -e $file ]
then
    echo "File exits"
else
    echo "File does not exit"
fi

File has read access
File has write access
File has execute permission
File is an ordinary file
This ia not a directory
File size is zero
File exits

#!/bin/bash 
name="yanke"
greeting="hello, "${name}"!"
greeting1="hello, ${name}!"
echo ${greeting} ${greeting1}

$ string="abcd"
$ echo ${#string}
4

$ string="Talk is cheap,show me the code!"
$ echo ${string:1:4}
alk

array_name=(value0 value1 value2 value3)

${array_name[index]}

#!/bin/bash 
Name[0]='Zara'
Name[1]='Qadir'
Name[2]='Mahnaz'
Name[3]='Ayan'
#        
echo "first index: ${Name[0]}"
echo "Second inde；inde；x: ${Name[1]}"
#       
echo "First Method:${Name[*]}"
echo "Second Method:${Name[@]}"
#       
length=${#Name[*]}
#   
#length=${#Name[@]}
#         
lengthn=${#Name[2]}
echo "The length of Name:${length}"
echo "The length of Name[2]:${lengthn}"

first index: Zara
Second inde；inde；x: Qadir
First Method:Zara Qadir Mahnaz Ayan
Second Method:Zara Qadir Mahnaz Ayan
The length of Name:4
The length of Name[2]:6

#!/bin/bash 
#echo       ：
#echo arg

#      
echo "\"It is a test\""

#    
name="OK"
echo "${name} It is a test"

#    
echo -e "OK! 
"  #-e     
echo "It's a test"

#   
echo -e "OK!\c"
echo "It's a test"

#       
echo "It is a test" > myfile

#       
echo '$name\"'

#        
echo `date`

"It is a test"
OK It is a test
OK! 

It's a test OK!It's a test
$name\" Thu Sep 29 22:08:53 CST 2016

#!/bin/bash 
#printf      ：
#printf format-string [arguments..]
#format-string        
#arguments     

echo "Hello, Shell!"
printf "Hello Shell
" #printf      

##     
printf "%-10s %-8s %-4s
"         kg
printf "%-10s %-8s %-4.2f
"      66.1234
printf "%-10s %-8s %-4.2f
"      48.6543
printf "%-10s %-8s %-4.2f
"      47.9876

#format-string    
printf "%d %s
" 1 "abc"

#         
printf '%d %s
' 1 "abc"

#         
printf %s abcdef

#          ，                  
printf %s abc def
printf "%s
" abc def
printf "%s %s %S 
" a b c d e f g h i j
#    guments,  %s NULL  ，%d  0   
printf "%s and %d
"

#!/bin/bash 
#for  
for loop in 1 2 3 4 5
do
    echo "The value is : $loop"
done

#while  
i=1
while(( ${i}<=5 ))
do
    echo $i
    let "i++"
done

#while      
#echo "  <CTRL-D>   "
#echo -n "          ："
#while read FILM
#do
# echo "  ！${FILM}      "
#done

#until  :     ， while   

#case    
echo "  1 4     "
echo -n "       ："
read aNum
case ${aNum} in
    1) echo "    1"
        ;;
    2) echo "    2"
        ;;
    3) echo "    3"
        ;;
    4) echo "    4"
        ;;
    *) echo "     1 4    "
        ;;
esac

#    
#break      
#continue      
while :
do
    echo -n "  1 5     ："
    read num
    case ${num} in
        1|2|3|4|5) echo "       $num"
            ;;
        *) echo "        1 5  ，    ！"
            break
            ;;
    esac
done


while :
do
    echo -n "  1 5     ："
    read num
    case ${num} in
        1|2|3|4|5) echo "       $num"
            ;;
        *) echo "        1 5  "
            continue
            echo "    "
            ;;
    esac
done

#!/bin/bash 
#    
#1、   function fun()   ，     fun()   ,      。
#2、    ，     ：return   ，    ，            ，     。 return    n(0-255)))

demoFuc()
{
    echo "Hello world!"
}

echo "--------      -----------"
demoFuc
echo "--------      -----------"


#        ：    return
fucWithReturn()
{
    echo "          "
    echo -n "        ："
    read num1
    echo -n "        ："
    read num2
    echo "        ${num1} ${num2}"
    return $((${num1} + ${num2}))
}

fucWithReturn
echo "  ：$? ."

#       :$n     

funWithParam()
{
    echo "      ：$1 ."
    echo "      ：$2 ."
    echo " 10    ：${10} ."
    echo "      ：$#  ."
    echo "       : $* ."
}

funWithParam 1 2 3 33 544 5 33 23 23 53 45 22 33

command << delimiter
    document
delimiter

#!/bin/bash
# author:    
# url:www.runoob.com

url="http://www.runoob.com"

#!/bin/bash
# author:    
# url:www.runoob.com

#   .     test1.sh   
. ./test1.sh

#             
# source ./test1.sh

echo "        ：$url"