Linux

Pandoc.

Underrated

Both linked projects have over 60k+ stars on GitHub

Pick one

tmsu is pretty cool - it creates a little db and uses that to track tags on your files without ever touching them. It also has it's own little tag based filesystem.

find?

Underrated or not widely known?

I love lazygit and I'm still surprised at how many people are shocked when they see it for the first time. Not exactly a command, but a very handy text UI tool.

For more elementary tools, I can't believe how many people know about ! and ctrl+r who don't also know about fc and edit-and-execute-command.

degit is a tool that will check out a git repo (or a specific branch or commit), but not set it up as a git repo. Basically just downloading a specific commit to a directory.

GNU datamash (https://www.gnu.org/software/datamash/alternatives/) - handy tool for data munching. There's also https://github.com/BurntSushi/xsv

Bat, a cat alternative.

Lsd, an ls alternative.

Procs, a ps alternative.

Renane, because it's great.

all of them

motion

After spending years dealing with shady freeware and junk software on windows, I was floored by how easy and nonchalantly I was able to set up a simple security camera on my PC

Lightweight sudo alternatives, hard to google too. I know ssu and rdo, please mention others.

People always sleep on script. It's badass and let's you do goofy things like this while keeping standard terminal formatting: https://github.com/StaticRocket/dotfiles/blob/043e9a56cc9515060188ec4642e4048c0dd6c000/dot_bashrc#L79-L94

ip eg:

# ip a
# ip a a 192.168.1.99/24 dev enp160

The first incantation - ip address (you can abbreviate whilst it is unambiguous) gets you a quick report of interfaces, MAC, IPs and so on. The second command assigns another IP address to an interface. Handy for setting up devices which don't do DHCP out of the box or already have an IP and need a good talking to.

Oh and you can completely set up your IP stack, interfaces and routing etc with it. Throw in nft or iptables (old school these days - sigh!) for filtering and other network packet mangling shenanigans.