how to generate unique string

Question

I want to transform an XML document into HTML. Some XML elements have links to others documents like:

In the H

Answer 1

I had to insert date at the beginning of the lines of a log file and it's done like below:

DATE=$(date +"%Y-%m-%d")
awk '{ print "'"$DATE"'", $0; }' /path_to_log_file/log_file.log

It can be redirect to another file to save