How To Run Multiple SSH Command On Remote Machine And Exit Safely

How To Run Multiple SSH Command On Remote Machine And Exit Safely

last updated in Categories , , , , , , , , ,

 

I have a backup sync program on local server. I have an ssh password less login set up, and I can run commands on an external server in bash script doing:
ssh root@server2 "sync; sync; /sbin/shutdown -h now"
How do I run multiple commands in bash on a remote Unix or Linux server? What is the best way to SSH in and run various unix commands in a bash shell?

[donotprint][/donotprint]There are various ways to run multiple commands on a remote Unix server. This page show the easiest way to ssh and run multiple commands in using bash shell. The syntax is as follows.

 

 

 

Simple bash syntax to run multiple commands on remote machine

Simply run command2 if command1 successful on a remote host called foo:
$ ssh bar@foo "command1 && command2"
For example, run uptime and date commands on a box named ‘centos7’ as ‘vivek’ user::
ssh vivek@centos7 "uptime && date"
Sample outputs:

 18:36:17 up 1 day,  8:14,  0 users,  load average: 1.02, 1.06, 1.05
Fri Jun  7 18:36:17 IST 2019

How To Run Multiple SSH Command

Run date and hostname commands:
$ ssh user@host "date && hostname"
You can run sudo command as follows on a remote box called server1.cyberciti.biz:
$ ssh -t vivek@server1.cyberciti.biz "sudo /sbin/shutdown -h now"
And, finally:
$ ssh root@server1.cyberciti.biz "sync && sync && /sbin/shutdown -h now"
How To Run Multiple SSH Command On Remote Linux or Unix Machine

Bash here document syntax to run multiple SSH command

The here document syntax tells the shell to read input from the current source (HERE) until a line containing only word (HERE) is seen:

ssh server1 << HERE
 command1
 command2
HERE

Here is another example to run a multiple commands on a remote system:

ssh vivek@server1.cyberciti.biz << EOF
 date
 hostname
 cat /etc/resolv.conf
EOF

With sudo command type:

ssh -t vivek@server1.cyberciti.biz << EOF
 sync
 sync
 sudo /sbin/shutdown -h 0
EOF

Pipe script to a remote server

Finally, create a script called “remote-box-commands.bash” as follows on your local server:

date
hostname
cat /etc/resolv.conf

Run it as follows on a remote server called nas02nixcrafthomeserver:
$ cat remote-box-commands.bash | ssh user@nas02nixcrafthomeserver
OR
cat remote-box-commands.bash | ssh -t vivek@nas02nixcrafthomeserver

How to ssh to multiple servers and run commands

One can use simple bash for loop as follows. In this example, run uptime command on three Linux server named box1, box2, and box3:

for s in box1 box2 box3
do
   ssh vivek@${s} uptime
done

Running local bash script on remote system

Create a shell script as follows:

#!/bin/bash
# Name: test.sh 
# Purpose: Run multiple commands on a remote box 
# ----------------------------------------------------
uptime
date
whoami

Now run it as follows on host named server1.cyberciti.biz:
ssh vivek@server1.cyberciti.biz 'bash -s' < /path/to/test.sh
OR run it on four servers:

for s in server{1..4}.cyberciti.biz
do
   ssh vivek@${s} 'bash -s' < /home/vivek/bin/test.sh
done

Please note that the -t option will get rid of "Sorry, you must have a tty to run sudo/insert your-command-here" error message. You can also use pssh (parallel ssh) for executing ssh in parallel on a number of Linux/Unix/BSD servers. For more info see your ssh and bash command man page:
$ man ssh
$ man bash
$ man sudo

And there you have it, multiple bash shell command run using nothing but ssh client/sever model. A better option is to use the ansible tool.

0 (0)
Article Rating (No Votes)
Rate this article
Attachments
There are no attachments for this article.
Comments
There are no comments for this article. Be the first to post a comment.
Full Name
Email Address
Security Code Security Code
Related Articles RSS Feed
Linux LVM recovery
Viewed 15355 times since Wed, Jan 23, 2019
10 Linux nslookup Command Examples for DNS Lookup
Viewed 9147 times since Sun, Sep 30, 2018
Build a simple RPM that packages a single file
Viewed 5976 times since Sat, Jun 2, 2018
Linux: Disks diagnostic using smartctl
Viewed 12262 times since Wed, Jul 25, 2018
Linux RAID Mdadm Cheat Sheet
Viewed 3480 times since Fri, May 15, 2020
LVM: Rename root VG/LV
Viewed 5555 times since Sat, Jun 2, 2018
Terminal based "The Matrix" like implementation
Viewed 978 times since Thu, Apr 18, 2019
red hat 7 tmpfiles service
Viewed 892 times since Thu, Oct 11, 2018
FIO (Flexible I/O) – a benchmark tool for any operating system
Viewed 18127 times since Wed, Jul 25, 2018
RHEL: Checking HBAs
Viewed 11659 times since Sun, May 27, 2018