shell 脚步统计自身执行次数

#!/bin/bash

if [ -e a.txt ]

then

n=$(cat a.txt)

else

n=0

fi

if expr $1 + 0 &>/dev/null

then

echo "$1 is number"

n=0

else

echo "$1 is not number please input number"

fi

let n++

echo $n > a.txt

cat a.txt