If you need to find out the time difference between bash outputs, you can use ts from the moreutils package.
To get started, you’ll need to install moreutils.
A simple apt-get install moreutils should do the trick.
Then all you need to do is to pipe your output to ts
Like:
echo -e "test\ntest\ntest" | ts
This will return a nice timestamp on each linebreak.
You can even customize the timestamp like:
echo -e "foo\nbar\nbaz" | ts '[%Y-%m-%d %H:%M:%S]'
[2011-12-13 22:07:03] foo
[2011-12-13 22:07:03] bar
[2011-12-13 22:07:03] baz
References: