Home
>
Software
>
Running a Program on a Remote Server Using SSH

Running a Program on a Remote Server Using SSH

How do you run a program on a remote server using ssh?

For this example we'll have two servers, one named Johnny and another named Cash. Both are running openssh. Our goal is to have a program on Johnny login to Cash and run a program on Cash. To make the task a little more complex we'll be using different users on each machine.

The first thing we'll need to do is generate public and private keys on Johnny. So, logged into Johnny as user 'boy' we create public and private keys by creating them in the .ssh directory as follows:

Johnny$> pwd

/home/boy/.ssh

Johnny$> ssh-keygen -t rsa -f sue

Generating public/private rsa key pair.

Enter passphrase (empty for no passphrase):

Enter same passphrase again:

Your identification has been saved in sue.

Your public key has been saved in sue.pub.

The key fingerprint is:

8d:e9:c0:g1:c7:1f:e3:b3:2f:38:12:aa:b5:3b:2e:b3 boy@Johnny

Johnny$>

In the example above we picked an arbitrary name, sue, to identify the files that hold the generated keys. When prompted to enter a passphrase (twice) we simply hit enter twice.

As the output of ssh-keygen indicates, the public key has been saved in a file named sue.pub.

The output of ssh-keygen implies, but doesn't indicate directly, that the private key is in a file named sue (Yes, a user named boy created a file named sue.)

Johnny$>ls -l

-rwx------ 1 sue suegrp 887 Oct 17 14:27 sue

-rwx------ 1 sue suegrp 223 Oct 17 14:27 sue.pub

The private key file, sue, will remain on Johnny for the reaminder of this exercise, but the public key must be moved to the remote server, Cash. Note that the .ssh directory itself, as well as the sue and sue.pub files should have permissions of 700.

Now you'll need to ftp the sue.pub file from Johnny to Cash. The user on Cash that we'll login as is user 'named'.

Johnny$> ftp Cash

Connected to Cash

220 Cash - Propery of Xyz. - Authorized users only

Name (Cash:boy): named

331 Password required for named.

Password:

230-Last unsuccessful login: Fri Oct 17 13:12:55 2003 on ftp from Johnny 230-Last login: Fri Oct 17 16:02:11 2003 on /dev/pts/1 from Johnny

230 User named logged in.

ftp> cd .ssh

ftp> mput sue.pub

mput sue.pub? y

200 PORT command successful.

150 Opening data connection for sue.pub.

226 Transfer complete.

224 bytes sent in 0.000781 seconds (280.1 Kbytes/s)

local: sue.pub remote: sue.pub

ftp>bye

221 Goodbye.

Johnny$>

Now we'll telnet into Cash and concatenate the sue.pub file into /home/named/.ssh/authorized_keys file.

Cash$> pwd

/home/named/.ssh

Cash$> cat sue.pub >> authorized_keys

Cash$> exit

Connection closed.

Johnny$>

Let's recap what we've done so far.

1) We've created public and private keys on Johnny.

2) We've ftp'd the public key file, sue.pub, from Johnny to Cash.

3) We've telnetted to Cash, and concatenated the contents of sue.pub into authorized_keys

We're now ready to manually login from Johnny to Cash using ssh.

Johnny$> ssh -i /home/boy/.ssh/sue named@Cash

The authenticity of host 'Cash (xxx.yyy.zzz.aaa)' can't be established.

RSA key fingerprint is 65:11:7d:ef:ed:a3:cc:34:d1:b5:ba:c9:16:22:31:23.

Are you sure you want to continue connecting (yes/no)? yes

================================================================

*** NOTICE TO ALL USERS ***

================================================================

Cash$>exit< /p>

Connection to Cash closed.

Johnny$>

Now on Johnny, create a shell script called 'boynamedsue.sh' with the following one line of contents and chmod the script to 777.

ssh -i /home/boy/.ssh/sue named@Cash /usr/bin/ls -l

Next, execute the script on Johnny.

Johnny$> boynamedsue.sh

================================================================

*** NOTICE TO ALL USERS ***

================================================================

-rwxrwxr-x 1 named namedgrp 10020 Oct 17 14:35 namedfile1.txt

-rw-r--r-- 1 named namedgrp 680 Aug 14 16:18 namedfile.html

-rw------- 1 named namedgrp 1148 Aug 18 09:51 mbox

drwxr-xr-x 2 named namedgrp 512 Jun 17 13:38 old

Johnny$>

You just executed a program on Johnny, that logged into Cash and ran a program (unix 'ls -l').

The next step you'll want to take is to replace the '/usr/bin/ls -l' command in the boynamedsue.sh program with the path and name of the program that you want to run.

About The Author

C.S. Deam is a small business owner. His eBook Computer Nuggets: Non-Techie Internet Tips For In-Laws, Out-Laws, and the Rest of Society is a great gift for non-techie family members and is available at www.linkertonpublishing.com where you can sign up for FREE E-Courses & Newsletters to help you on your path to self-employment.

house refresh service Lincolnshire ..

In The News:

Cybersecurity firm Infoblox reveals that over 90 percent of parked domains now redirect visitors to scams and malware, making simple typos extremely dangerous.

The Fox News AI Newsletter covers the latest artificial intelligence technology advancements, including the challenges and opportunities AI presents now and for the future.

GPT-5.2 is now live for all ChatGPT users with improved coding, writing and image interpretation, with Kurt Knutsson offering his review.

New iPhone replacement scam uses pressure tactics and fake carrier calls to steal devices from buyers. Criminals claim shipping errors and demand urgent returns.

Amazon Ring's new facial recognition feature sparks privacy controversy as Electronic Frontier Foundation critics argue the AI upgrade expands surveillance risks.

New Android banking trojan Sturnus steals credentials, reads encrypted messages and controls devices.

Denmark's 3D-printed student village proves automation builds 36 apartments faster than traditional methods. Skovsporet project shows housing future.

Discover Android's new Sound Notifications feature that alerts you to smoke alarms, doorbells, and baby cries even when wearing headphones.

New SantaStealer malware reportedly threatens holiday shoppers with password theft. This Christmas-themed info-stealer targets browsers and crypto wallets.

The Christmas season brings a surge in Netflix phishing scams targeting shoppers with fake emails. Stacey P received convincing scam but verified account first.

San Francisco Giants invite Jamie Grohsong to throw ceremonial first pitch at Oracle Park after he learned to play baseball with a bionic hand following an injury.

FBI warns cybercriminals are stealing family photos from social media to create fake proof of life images in virtual kidnapping scams targeting victims.

Instagram's new 'Your Algorithm' tool lets you control your Reels feed in real time. The app now gives you power to customize what videos you see.

Major Marquis fintech breach exposes 400,000-plus Americans' data through unpatched SonicWall vulnerability, with Texas hardest hit at 354,000 affected.

Free up iPhone storage fast by clearing large photos and videos from Messages app. Simple steps for iOS users to delete attachments without losing chats.

Scammers are flooding inboxes with fake tracking alerts that mimic real carriers, exploiting the holiday rush to steal logins and personal data.

The Fox News AI Newsletter brings you the latest news on AI technology advancements and the challenges and opportunities AI presents now and for the future.

Texas family reunites with missing 11-year-old cat Grayson after 103 days using Petco Love Lost's AI photo matching technology and community help.

Tired of AI customer service loops? These insider tricks help you escape "frustration AI" and get real human help when you need it most for urgent issues.

Unlock richer audio from your streaming apps with simple tweaks to volume normalization, equalizer settings, and quality preferences for cleaner sound.

Scammers are sending fake Facebook settlement payout emails that mimic legitimate notices from the privacy settlement administrator to deceive users.

Holiday shopping scams surge as fake refund emails target distracted consumers during Black Friday and holiday seasons, costing Americans billions annually.

The AI-powered IRMO M1 exoskeleton features four modes, including turbo, eco, training and rest for hiking, running, cycling and sports with eight-hour battery life.

OpenAI announced upgrades for its ChatGPT Images platform on Tuesday, saying the program can now make more precise edits and produce images more quickly.

Chrome for Android now turns web articles into AI-powered podcast conversations. Get hands-free browsing with Google Gemini's natural audio summaries.

Running a Program on a Remote Server Using SSH

Software