I learnt about termux from a friend on IRC recently. It looked super gimmicky to me at first, but it eventually proved to be useful. Here's what I use it for:

rsync

Ever since I degoogled my android device, syncing files between my phone and my PC has always been a pain. I’m looking at you MTP. But, with termux and sshd all set up, it's as simple as:

$ arp
Address         HWtype  HWad ...
192.168.43.187  ether   d0:0 ...

$ rsync -avz 192.168.43.187:~/frogs ~/pics/frogs

ssh & tmux

My phone doubles as a secondary view into my main machine with ssh and tmux. When I am away from my PC (read: sitting across the room), I check build status and IRC messages by sshing into a tmux session running the said build or weechat.

file uploads

Not being able to access my (ssh-only) file host was crippling. With a bash instance on my phone, I just copied over my ssh keys, and popped in a file upload script (a glorified scp). Now I just have to figure out a way to clean up these file names …

~/storage/pictures/ $ ls
02muf5g7b2i41.jpg  7alt3cwg77841.jpg  cl4bsrge7id11.png
mtZabXG.jpg        p8d5c584f2841.jpg  vjUxGjq.jpg

cmus

Alright, I don't really listen to music via cmus, but I did use it a couple times when my default music player was acting up. cmus is a viable option: