can I redirect file as input to notify-send?

Solution 1:

http://www.commandlinefu.com/commands/view/4460/pipe-output-to-notify-send

says

echo 'information overlord' | while read OUTPUT; do notify-send "$OUTPUT"; done

Solution 2:

Im not sure what you want to do or what kind of file you want to display but man notify-send says

notify-send [OPTIONS] <summary> [body]

Summary being a title, so for example, the basename of your file.

So what you can do is

notify-send -u critical -t 3000 "$(basename ~/ved)" "$(cat ~/ved)"

But be aware that notify-send won't print long text file, it's not its job.

Also, I don't know for you or everyone else, but the -t option never worked for me, time being always 10s. I've read it was a bug a long time ago and it's still not working in 12.04.