Run a local script on a remote host

Overview

Run bash and python scripts remotely, without modification, without copying files.

Details

I want to run such a script

sample.sh

#!/bin/bash

for arg in init ${@};do
    echo "$(date +%Y-%m-%dT%H:%M:%S) $(hostname) ${arg}"
    sleep 1
done

$ ./sample.sh a b c
2015-12-22T11:30:26 local-host init
2015-12-22T11:30:27 local-host a
2015-12-22T11:30:28 local-host b
2015-12-22T11:30:29 local-host c

Basic idea

1. With ssh, you can submit a script to stdin of a remote shell.

$ cat sample.sh | ssh user@remote-host
2015-12-22T11:31:43 remote-host init

2. bash can receive the contents of stdin as a file

$ cat sample.sh | bash <(cat -) a b c
2015-12-22T11:33:47 local-host init
2015-12-22T11:33:48 local-host a
2015-12-22T11:33:49 local-host b
2015-12-22T11:33:50 local-host c

3. With the here document, you can run the script without creating a file

$ cat << 'EOT' | bash <(cat -) a b c
> for arg in init ${@};do
>     echo "$(date +%Y-%m-%dT%H:%M:%S) $(hostname) ${arg}"
>     sleep 1
> done
> EOT
2015-12-22T11:40:17 local-host init
2015-12-22T11:40:18 local-host a
2015-12-22T11:40:19 local-host b
2015-12-22T11:40:20 local-host c

Implementation

Such a script

rdosh.sh

#!/bin/bash
echo -e "cat << 'EOT' | bash <(cat -) ${@:2}\n$(cat ${1}|sed -e 's/\\/\\\\/g')\nEOT"

• If you leave cat, \ n etc. will be escaped, so escape \ with sed

Experiment

$ ./rdosh.sh sample.sh a b c | ssh user@remote-host
2015-12-22T11:42:48 remote-host init
2015-12-22T11:42:49 remote-host a
2015-12-22T11:42:50 remote-host b
2015-12-22T11:42:51 remote-host c

did it

python too

Such a script

sample.py

#!/usr/bin/env python
# -*- coding: utf-8 -*-

import sys
import os
import time
for arg in ["init"]+sys.argv[1:]:
    sys.stdout.write("{0} {1} {2}\n".format(time.strftime("%Y-%m-%dT%H:%M:%S"),os.uname()[1],arg))
    sys.stdout.flush()
    time.sleep(1)

rdopy.sh

#!/bin/bash
echo -e "cat << 'EOT' | python <(cat -) ${@:2}\n$(cat ${1}|sed -e 's/\\/\\\\/g')\nEOT"

python also worked

$ ./sample.py a b c
2015-12-22T13:20:29 local-host init
2015-12-22T13:20:30 local-host a
2015-12-22T13:20:31 local-host b
2015-12-22T13:20:32 local-host c
$ ./rdopy sample.py a b c | ssh user@remote-host
2015-12-22T13:20:46 remote-host init
2015-12-22T13:20:47 remote-host a
2015-12-22T13:20:48 remote-host b
2015-12-22T13:20:49 remote-host c