Best practice for storing token/credential using cli tools

Question

I want to make cli tools just like firebase or github using yargs. so firebase does have this command "firebase login". I wonder how and where do they store the token/credential. If it's web browser I could store it in the cookie or local storage but using cli I don't have any clue.

yargs(Deno.args)
  .command('login', 'make a post request to my oauth server', (yargs: any) => {
     OauthClient.post({ username: yargs.username, password: yargs.password })
                .then(r => { 
                   // what to do with this token????
                   const token = extractToken(r.headers.authorization)
                })
  })
  .strictCommands()
  .demandCommand(1)
  .parse()