Script to add timestamp to every line of a log file

timestamp.md

How to add a timestamp to every line of a log file

There are occasions where you would like to have a log file include a timestamp for each line. The following script will allow you to do just that.

timestamp.sh

#!/bin/bash
while read x; do
    echo -n `date +\[%Y-%m-%d\ %H:%M:%S.%3N]`;
    echo -n " ";
    echo $x;
done

sample cron usage

... /path/to/command 2>&1 | /path/to/timestamp.sh >> /var/log/command.log