shell 日期循環

#!/bin/bash
# $author:

export PATH=/usr/sbin:/usr/bin:/sbin:/bin

datebeg="2015-06-15"
dateend="2015-06-28"

beg_s=`date -d "$datebeg" +%s`
end_s=`date -d "$dateend" +%s`

while [ "$beg_s" -le "$end_s" ];do
         day=`date -d @$beg_s +"%Y%m%d"`;
         echo $day;
         beg_s=$((beg_s+));
done