DATEPATTERN="^[0-9]{4}-[0-9]{1,2}-[0-9]{1,2}$"
if [[ "$STARTDATE" =~ $DATEPATTERN ]] && [[ $ENDDATE =~ $DATEPATTERN ]]; then :
else
echo "date format is invalid!"
exit;
fi

if [[ "$file" =~ 'start' ]]
或if [[ "$file" =~ "start" ]]

#!/usr/bin/ksh
file="10start11.s"
if [[ "$file" =~ "start" ]]
then
echo "success"
else
echo "failed"
fi

flag=`echo $file |awk '/start/'`
if [ "$flag" = "" ];then
echo "success"
else
echo "failed"
fi

if[判断条件]
then
command1
command2
……..
last_command
fi