[: read: unarg operator expected?

wwmshe

原代码如下：
fsmax="85"
maillist1="cold@163.com"
maillist2="hot@163.com"
df -k | grep '/dev/h' | awk '{print $1,$5,$6}'>mailfile
mail -s "Filesystem Information" $maillist1 < mailfile
mail -s "Filesystem Information" $maillist2 < mailfile
df -k | grep '/dev/h' | awk '{print $5}'>outfile
while [ read fsvalue ]
do
        fsvalue=$(echo $fsvalue | sed 's/\%//')
        if [ $fsvalue -lt $fsmax ]
        then
        mail -s "Full Disk" $maillist1 < outfile
        mail -s "Full Disk" $maillist2 < outfile
        fi
done<outfile

ha_

while read line
do
...
done < file1