shell判断参数是否是数字

#!/bin/bash    ## 方法1,有点问题#if [[ "$1" =~ "^[[:digit:]]*$" ]];then#if [[ "$1" =~ "^[0-9]+$" ]];then#    echo "$1 is number."#else#    echo 'no.'#fi   ## 方法2, 可以，不过不是bash实现的，是使用了grep的正则#if grep '^[[:digit:]]*$' <<< "$1";then#    echo "$1 is number."#else#    echo 'no.'#fi   ## 方法3#if [ "$1" -gt 0 ] 2>/dev/null ;then#    echo "$1 is number."#else#    echo 'no.'#fi   ## 方法4,case#case "$1" in#    [1-9][0-9]*) #        echo "$1 is number."#        ;;#    *)  #        ;;#esac   ## 方法5,awk#echo $1| awk '{print($0~/^[-]?([0-9])+[.]?([0-9])+$/)?"number":"string"}'   ## 方法5,awk#if [ -n "$(echo $1| sed -n "/^[0-9]\+$/p")" ];then#    echo "$1 is number."#else#    echo 'no.'#fi    ## 方法6,exprexpr $1 "+" 10 &> /dev/nullif [ $? -eq 0 ];then    echo "$1 is number"else    echo "$1 not number"fi