i have a file which contains data seperated by comma. i want to replace text after 3rd occurrence of a comma.
the input file looks like this
abcdef,11/02/2015 11:55:47,1001,1234567812345678,12364,,abc
abcdefg,11/02/2015 11:55:47,01,1234567812345678,123,,abc
abcdefhih,11/02/2015 11:55:47,1001,1234567812345678,1234,,abc
abcdef,11/02/2015 11:55:47,001,1234567812345678,1236487,,abc
i want the output to be like
abcdef,11/02/2015 11:55:47,1001,1234-5678-1234-5678,12364,,abc
abcdefg,11/02/2015 11:55:47,01,1234-5678-1234-5678,123,,abc
abcdefhih,11/02/2015 11:55:47,1001,1234-5678-1234-5678,1234,,abc
abcdef,11/02/2015 11:55:47,001,1234-5678-1234-5678,1236487,,abc
i was able to replace the text with "-" after 4 digits using awk and sed like below but not sure how to get it work within file and then redirect it to a different file
awk -F',' '{print $4}' file | sed -n -e "s_\(....\)\(....\)\(....\)\(....\)_\1-\2-\3-\4_p"