Sox is your friend:
sox -v 2.0
will double the volume, basically.
There's much more to it, of course. But, sox has a great man page.
Linux for blind general discussion writes:
> I would like sometimes to use my pc to amplify audio; my hearing is very porr.
> I would like to just have the mic or line-in amplified and come to my
> I used to know how to do this but cannot remember.
> Can you suggest the easiest way using command-line command?
> Ubuntu 16.04lts, x86/64 with alsa and many audio programs on there.
> Blinux-list mailing list
Linux Foundation Fellow
Executive Chair, Accessibility Workgroup: http://a11y.org
The World Wide Web Consortium (W3C), Web Accessibility Initiative (WAI)
Chair, Accessible Platform Architectures http://www.w3.org/wai/apa
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