update csv field with current time stamp value in shell script

Question

I am after a bash script mainly to update a CSV file containing a only row like below:

08/01/2017 2:58,0.32967,0.29304,nan,nan,0.989011,0.671551,12.68,83.1975,11.0937

So the requirement is to update the first column ie timestamp value with the current timestamp value (in the above format) every time when I run the script to change the value.

Answer 1

here is a sed pattern which seems to work for your case:

sed -i "s|^[^,]*|`date '+%d/%m/%Y %H:%M'`|g" <yourfile>

This code will take everything from beginning which is not a coma (and will stop when it encounters one) and will replace it with the output of date linux command with a good formating. the -i options allows you to live edit your file.