shell脚本传入的参数变量是全局变量

#!/bin/bash
testtranfun(){
    echo "++++++++++"
    echo $a
    echo "++++++++++"
}
parse_arg(){
for i in "$@";do
    if [[ $i = *"="* ]];then
        eval "$i"
    fi
done
}
main(){
testtranfun
parse_arg "$@"
echo $a
echo $b
testtranfun
}
main "$@"
echo "##########"

testtranfun

说明传入的参数是一个全局变量