editing delimited file

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1

I have a comma delimited file with following data

text1,text2,text3,text4,date1,date2,textn,textn+1

I want to edit ONLY the dates in the file. date1 and date2 to some other value. say date3 and date4 respectively. I want to leave the text as it is.

I don't know the value for date and 2. So I cannot do direct search and replace. I just have to go by the position. Here the date1 and 2 occupy 5th and 6th position.

any simple way to do this?

2

A point to start from:

#! /bin/bash

INPUT="text1,text2,text3,text4,date1,date2,textn,textn+1"

F_5=$( echo $INPUT | awk -F ',' '{ print $5 }' )
F_6=$( echo $INPUT | awk -F ',' '{ print $6 }' )

echo "5th field: '$F_5'"
echo "6th field: '$F_6'"

exit 0

[house@leonov] sh test.bash
5th field: 'date1'
6th field: 'date2'
3

this is just going to display the dates which is not what I want. I want to edit the dates thru a script.