按索引访问shell脚本参数

Question

当你进入shell编程时,我确信这是一个明智的选择.不幸的是我不是,而且我很难过......

我需要验证传递给shell脚本的参数.我还想存储在数组中传递的所有参数,因为我稍后需要进一步分离.

我有一个参数"-o",必须后跟0或1.因此,我想检查以下参数是否有效.这是我试过的:

# Loop over all arguments
for i in "$@"
do
    # Check if there is a "-" as first character,
    # if so: it's a parameter
    str="$i"
    minus=${str:0:1}

    # Special case: -o is followed by 0 or 1
    # this parameter needs to be added, too
    if [ "$str" == "-o" ]
    then
        newIdx=`echo $((i+1))`   # <-- problem here: how can I access the script param by a generated index?
        par="$($newIdx)"

        if [[ "$par" != "0" || "$par" != "1" ]]
        then
            echo "script error: The -o parameter needs to be followed by 0 or 1"
            exit -1
        fi
        paramIndex=$((paramIndex+1))

    elif [ "$minus" == "-" ]
    then
        myArray[$paramIndex]="$i"
        paramIndex=$((paramIndex+1))
    fi
done

我尝试了各种各样的东西,但它没有用......如果有人能够阐明这一点,我将不胜感激!

谢谢

Answer 1

在bash,您可以使用间接参数扩展来访问任意位置参数.

$ set a b c
$ paramIndex=2
$ echo $2
b
$ echo ${!paramIndex}
b