Shell Programming and Scripting

Hi All,
I have a file, say test.dat which is "|" separated. It has 50K records in it. One of the field in the file has the data in the format 'mm/dd/yyyy'. I need to edit the file by changing the format to 'yyyy/mm/dd' in the same field where as the rest of the data remain untouched. Please review the example mantioned below.

test.dat
---------
abcd|ret|12/22/2004|adsf
cdfe|re|05/23/2004|fg
fs|tre|08/22/1889|tref

outputfile(same test.dat)
---------
abcd|ret|2004/12/22|adsf
cdfe|re|2004/05/23|fg
fs|tre|1889/08/22|tref

All I know about AWK, it will be much faster than any other scripting language. Even I prefer to do the same in the commad line itself.
Thanks in advance.

Thanks & Regards,
Rin11... :-)

Code:

BEGIN {
   FS=OFS="|"
}
{
  split($3, f3, "/")
  $3=f3[3] "/" f3[1] "/" f3[2]
  print
}

Code:

awk -F"|" '{ printf "%s|%s|%d/%d/%d|%s\n", $1,$2,substr($3,7,4),substr($3,1,2),substr($3,4,2),$4}'  filename