bash搜索大文件

# Name: bigfiles
# Purpose: Use the find command to find any files in the root
# partition that have not been modified within the past n (any
# number within 30 days) days and are larger than 20 blocks
# (512-byte blocks)

if (( $# != 2 ))          # [ $# -ne 2 ]
then
 echo  "Usage:   $0 mdays size " 1>&2
 exit 1
fi
if (( $1 <  0 || $1 > 30 ))     # [ $1 -lt 0 -o $1 -gt 30 ]
then
 echo "mdays is out of range"
 exit 2
fi
if (( $2 <= 20 ))      # [ $2 -le 20 ]
then
 echo "size is out of range"
 exit 3
fi

find / -xdev -mtime $1 -size +$2