Decode a JWT via command line

jwt-decode.sh

# will not work in all cases, see https://gist.github.com/angelo-v/e0208a18d455e2e6ea3c40ad637aac53#gistcomment-3439904

function jwt-decode() {
  sed 's/\./\n/g' <<< $(cut -d. -f1,2 <<< $1) | base64 --decode | jq
}

JWT=eyJhbGciOiJIUzI1NiIsInR5cCI6IkpXVCJ9.eyJzdWIiOiIxMjM0NTY3ODkwIiwibmFtZSI6IkpvaG4gRG9lIiwiYWRtaW4iOnRydWV9.TJVA95OrM7E2cBab30RMHrHDcEfxjoYZgeFONFh7HgQ

jwt-decode $JWT

Oh, beware though that basenc complains about missing = signs, even in --base64url mode, so you'll also need to suppress stderr.