ローカルマシン からCloud Shellに接続(ssh, scp, mount)する ref: https://qiita.com/flatfisher/items/1d6ffe94787b77e3f2ee

file0.txt

$ gcloud alpha cloud-shell ssh 

API [cloudshell.googleapis.com] not enabled on project
Would you like to enable and retry (this will take a
few minutes)? (y/N)?  y //Cloud Shell API をONにする

your_account_name@cloudshell:~ (project_id)$ //ssh接続できた

file1.txt

$ gcloud config set project [your_project_id]
$ gcloud config set account hogehoge@gmail.com
$ gcloud config list

[core]
account = hogehoge@gmail.com
disable_usage_reporting = False
project = [your_project_id]

Your active configuration is: [your_project_id]

//configを複数持つことも可能
$ gcloud config configurations list
NAME         IS_ACTIVE  ACCOUNT                  PROJECT        DEFAULT_ZONE  DEFAULT_REGION
default      False      hogehoge@gmail.com  [your_project_id_1]
flatfish-jp  True       hogehoge@gmail.com  [your_project_id_2]

file2.txt

$gcloud alpha cloud-shell ssh --command=ls
fileA
fileB
fileC

file3.txt

$gcloud alpha cloud-shell scp localhost:`pwd`/filea cloudshell:~/

$gcloud alpha cloud-shell ssh --command=ls
filea

file4.txt

$gcloud alpha cloud-shell scp cloudshell:~/filea  localhost:`pwd`/

$ls
filea

file5.txt

$ mkdri testdir
$ gcloud alpha cloud-shell get-mount-command testdir/
sshfs hogehoge@hogehoge: testdir/ -p 6000 -oIdentityFile=$HOME/.ssh/google_compute_engine -oStrictHostKeyChecking=no

//出て結果をそのまま実行すると testdir/ にマウントされる
$ sshfs hogehoge@hogehoge: testdir/ -p 6000 -oIdentityFile=$HOME/.ssh/google_compute_engine -oStrictHostKeyChecking=no

//マウント解除
$ diskutil unmount testdir