u01 Occupying More space

   Dear Seniors
Yesterday I found the following file

-rw-rw---- 1 oracle oinstall 5079144602 Aug 15 18:13 nmh1_diag_9335.trc

has all of a suddern reached upto 5 Gb and It is occupying more space and I would like to remove this file. 
my space in Location /u01 is 100%full 

The out put is as follows

Filesystem             size   used  avail capacity  Mounted on
/dev/md/dsk/d0          20G   5.1G    14G    27%    /
/devices                 0K     0K     0K     0%    /devices
ctfs                     0K     0K     0K     0%    /system/contract
proc                     0K     0K     0K     0%    /proc
mnttab                   0K     0K     0K     0%    /etc/mnttab
swap                    18G   1.0M    18G     1%    /etc/svc/volatile
objfs                    0K     0K     0K     0%    /system/object
fd                       0K     0K     0K     0%    /dev/fd