when I fire 'ls' for file 'moh' which is not present.
getting error message on output
"ls: 0653-341 The file moh does not exist."
how to supress out this message from being displayed when file do not exist

Unix commands write to either stdout or stderr. You can send stderr to a file

ls 2> errfile moh

or to /dev/null

ls 2> /dev/null moh

Another method is turning stderr off:

ls 2>&- moh