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.

top rated cleaning service Lake Forest ..

In The News:

Holiday scams spike during Black Friday and Cyber Monday as criminals exploit your leaked personal data. Learn how to protect yourself from fake stores and phishing.

Commerce Department proposes TP-Link router ban over Chinese security risks. Learn how this potential prohibition could affect your home network and devices.

Hyundai AutoEver America suffered a data breach affecting 2,000 current and former employees, exposing names, Social Security numbers and driver's license information.

Washington court rules automated license plate reader images are public records, even when stored by vendors like Flock Safety, setting precedent for transparency.

Fake airline texts claiming flight cancellations are targeting travelers with convincing scams. Learn how cybercriminals steal personal data and credit card info.

Discover how iOS 26's new Adaptive Power feature automatically extends iPhone battery life by learning your usage patterns and adjusting performance intelligently.

New TikTok malware campaign tricks users into running PowerShell commands that download Aura Stealer, which steals credentials and authentication tokens.

Gaia Family offers fixed upfront pricing for IVF cycles with unlimited embryo transfers and financial protection, partnering with over 100 U.S. fertility clinics.

The Jetsons Act aims to position Pennsylvania as a leader in advanced air mobility by establishing regulations for hybrid ground-air vehicles.

Fake Geek Squad invoice emails are targeting users with convincing charges and urgent phone numbers to steal personal information and money.

Fox News Digital's artificial intelligence newsletter digs into a robot in Russia that faceplanted, George Clooney's alarm and OpenAI's rivalry with the New York Times.

Major data breach at Conduent exposes personal information of 10+ million people. Government contractor hit by cyberattack affecting Medicaid, child support systems.

Texas startup Janta Power raises $5.5M for innovative vertical solar towers that generate 50% more energy than traditional panels while using just one-third the land.

NASA's twin ESCAPADE spacecraft launched aboard Blue Origin's New Glenn rocket Thursday afternoon from Cape Canaveral, beginning their journey to Mars with arrival expected in 2027.

Learn how to set email reminders on iPhone and Android so you never forget to reply again. Simple built-in features help you stay organized and on top of messages.

Discover how Apple's passkeys revolutionize Mac security by replacing vulnerable passwords with biometric authentication and encryption for ultimate protection.

New survey reveals 78% of parents fear AI scams targeting their kids, yet nearly half haven't discussed these threats. Learn why this dangerous gap exists.

Chrome now autofills passport and driver's license info automatically. Google's latest browser update adds official document support with encryption and user control.

Scammers impersonate Department of Veterans Affairs employees claiming veterans owe money, but real VA communications only direct to VA.gov or official channels.

The AltoVolo Sigma hybrid-electric aircraft flies 500 miles at 220 mph while operating 80% quieter than helicopters, featuring safety systems and compact design.

Google search scam alert: fake customer service numbers can give scammers remote control of your phone. Learn how to spot these traps and protect yourself.

Electric vehicles overtake gas cars in total CO2 savings after just two years of driving, with emissions benefits growing over time as power grids get cleaner.

Louvre Museum reportedly used "Louvre" as password for surveillance system during $100M jewel heist. Learn how weak passwords put even famous institutions at risk.

Bipartisan AI jobs bill from Sens. Hawley and Warner would require companies to report AI-related layoffs and hiring to Department of Labor quarterly.

Joe A. from Shelton, Connecticut, lost $228,000 to a ZAP Solutions cryptocurrency investment scam after his divorce, highlighting rising online fraud.

Running a Program on a Remote Server Using SSH

Software