Condition checking in UNIX

Shell Programming and Scripting
1

i have a script where i have to find the age of a file,

if [ -n "`find $DATA_DIR/1181*.dat -mtime -20`" ]
         then
         echo "dnb file is present for the monthly load"  >> $RUNLOG
         dnb="1"
        else
         echo "dnb file has not arrived yet"  > $ERRLOG
         dnb="0"
        fi

i know the file is available so when i am echoing the value of $dnb, it is returning 1....
but later on when i am using this $dnb variable while condition checking then i am getting some error:

if [$dnb ==`1`];
         then
         cat $RUNLOG | mailx -s "Success: All the files are arrived for RDW monthly load, below is the status of files" "$MAI
L_DL"
        else
         cat $ERRLOG | mailx -s "Attention: All the files are still not arrived for RDW monthly load, below is the status of
files" "$MAIL_DL"
        fi

instead of going to cat $runlog condition it is going to display $errlog and another error which i am getting is :

RDW_file_check.ksh[87]: 1: not found

please suggest..

2

use below condition

if [ $dnb -eq 1 ]
then
3

thanks a lot Pravin, but i have 1 more requirement now..

i want to redirect the output of a file in multiple files located at different locations:

 ls -ltr $DATA_DIR/1181*.dat  >>$RUNLOG

----here i am redirecting it to $RUNLOG and i want it to redirect to $ERRLOG, some other location also

i hope u'll be able to help me on this.

4 
ls -ltr $DATA_DIR/1181*.dat  | tee -a $RUNLOG $ErrLOG 1>/dev/null