How to remove the milliseconds from timestamps with sed?

Question

My input file is as follows:

12/13/2011,07:14:13.724,12/13/2011 07:14:13.724,231.56.3.245,LasVegas,US

I wish to get the following:

<         


        

Answer 1

Since the sed solution has already been posted, here is an alternate awk solution:

[jaypal:~/Temp] cat inputfile
12/13/2011,07:14:13.724,12/13/2011 07:14:13.724,231.56.3.245,LasVegas,US

[jaypal:~/Temp] awk -F"," -v ORS="," '
{for(i=1;i

Explanation:

1. Set the Field Separator to , and Output Record Separator to ,.
2. Using a for loop we will loop over each fields.
3. Using an if loop we would do substitution to the fields when the for loop parses over second and third fields.
4. If the fields are not 2nd and 3rd then we just print out the fields.
5. Lastly since we have used the for loop for we just print out $NF which is the last field. This won't cause a , to be printed after last field.