linux经常使用shell变量 $? $$ $@ $#

#!/bin/bash
echo "传入的参数个数"  $#
echo "运行的脚本名字为:"  $0
echo "传入的第一个参数为:" $1
echo "传入的第二个参数为:" $2
echo "传给脚本的参数列表" $@
echo "传入的参数列表:" $*
echo "脚本运行的当前进程ID:" $$
echo "显示命令的退出状态,0表明成功,其余表明错误" $?
for (( i=1; i<=$#; i++ ))
do
        echo "$i"
done
echo "-------------------------------------"

for value in $@
do
        echo $value
done
echo "-------------------------------------"

for value1 in $*
do
        echo $value1
done