There are numerous programmes (e.g.
moreutils), and various bash one-liners to prepend the output of a command/pipe with the timestamp of when that line was 'printed'.
However is there a command that, for each line that it gets, will print the time since the command started (and/or when it first saw a line), and the current line? So rather than print the current time, it'll print how long since that command started? (aswell as the line aswell)
When running commands that take a while, and spew a lot of output, it can be helpful to know how long you've been looking at it.
It would be trivial to whip a simple command up, but I don't want to re-invent the wheel.
This is on an Ubuntu Linux system.