Hỏi về lập trình Shell - bước cơ bản đầu tiên

$ chmod 755 myscript.sh

$ ./myscript.sh

#/bin/bash

# input an array of elements
function input()
{
    echo -n "n= "
    read n
    
    for ((i=0; i<n; i++))
    do
        echo -n "a[$i] " =
        read a[$i]
    done
}

#max of two numbers
function max2nums()
{
    if [ "$1" -gt "$2" ]; then
        max1=$1
        echo $1
    else
        max1=$2
        echo $2
    fi
    return $max1
}

#max of an array
function maxs()
{
    max=${a[0]}
    for ((i=1; i<n; i++))
    do 
        max=$(max2nums ${a[$i]}  $max)
    done
    echo "max = $max"
}

input
maxs

exit $?

tisina@debianTH:~$ ./maxs.sh
./maxs.sh: line 9: syntax error near unexpected token `('
./maxs.sh: line 9: `    for ((i=0; i<n; i++))'

#/bin/bash

# input an array of elements
function input()
{
    echo -n "n= "
    read n
    
   for i in $( seq 1 n )      
    do
        echo -n "a[$i] " =
        read a[$i]
    done
}

#max of two numbers
function max2nums()
{
    if [ "$1" -gt "$2" ]; then
        max1=$1
        echo $1
    else
        max1=$2
        echo $2
    fi
    return $max1
}

#max of an array
function maxs()
{
    max=${a[0]}
    for ((i=1; i<n; i++))
    do 
        max=$(max2nums ${a[$i]}  $max)
    done
    echo "max = $max"
}

input
maxs

exit $?

tisina@debianTH:~$ ./maxs.sh
./maxs.sh: line 10: syntax error near unexpected token ` '
./maxs.sh: line 10: `    do'

> chmod 755 maxs.sh
foo@bar:/tmp
> ./maxs.sh
n= 10
a[0]  =2
a[1]  =3
a[2]  =4
a[3]  =5
a[4]  =6
a[5]  =1
a[6]  =2
a[7]  =3
a[8]  =4
a[9]  =2
max = 6