[bloopernova]

Knowing Unix/Linux command line tools will broaden the foundation upon which your other knowledge is built.

Knowing those tools will also simplify local development if you're running code in dev/test VMs or even containers.

Plus web dev is dealing a lot in text. Unix command line tools deal a lot in text.

I am, of course, biased as all heck. I'm a Unix sysadmin who does devops stuff too, so I like to think everyone should know the same thing as me.

Networking is vital too. Being able to understand just basics of what should be happening in a local subnet is very useful. Knowing about TCP ports and their states can also help debug certain problems.

All those extras make you stand out as a hyper-producer or guru rather than a run of the mill never stand out from the pack developer. There's definitely room in the world for both types, but gurus get the attention and respect.