I just copy and paste into a local text file, but I bet there’s a tool if you want to do it programmatically already (unless curl’ing is your idea of fun!)

Copy your session token into .token then:

curl "https://adventofcode.com/2024/day/$DAY/input" --header "Cookie: $(cat .token)" > input.txt

You could open the dev console in the browser and copy the curl command off the network tab

The command line tool included with this python library does just what you want once you paste your session token into an environment variable:

https://github.com/wimglenn/advent-of-code-data

You can use Firefox: "Copy as cUrl" (https://superuser.com/a/1382425)

Assuming you already opened it in a web browser, why not right click the page and choose "Save As"?

I have this script:

  #!/bin/sh
  set -e
  curl "https://adventofcode.com/${YEAR:?}/day/${DAY:?}/input" --cookie "session=$(cat .token)"

then: YEAR=2024 DAY=1 ./aocdata