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Running Commands on a Remote Linux / UNIX Host

You would like to execute a command on a remote Linux/FreeBSD/Solaris/UNIX host and have the result displayed locally. Once result obtained it can be used by local script or program. A few examples:
=> File system and disk information

=> Get user information

=> Find out all running process

=> Find out if particular service is running or not etc

You can use rsh or ssh for this purpose. However, for security reason you should always use the ssh and NOT rsh. Please note that remote system must run the OpenSSH server.

Syntax for running command on a remote host:
ssh [USER-NAME]@[REMOTE-HOST] [command or script]

Where,

  • ssh: ssh (SSH client) is a program for logging into a remote machine and for executing commands on a remote machine.
  • USER-NAME: Remote host user name.
  • REMOTE-HOST: Remote host ip-address or host name, such as fbsd.cyberciti.biz.
  • command or script: Command or shell script is executed on the remote host instead of a login shell.

Examples

(A) Get disk information from a server called www1.cyberciti.biz:
$ ssh vivek@www1.cyberciti.biz df -h

(B) List what ports are open on remote host
$ ssh vivek@www1.cyberciti.biz netstat -vatn

(C) Reboot remote host:
$ ssh root@www1.cyberciti.biz reboot

(D) Restart mysql server (please note enclosed multiple command line arguments using a single or double quotes)
$ ssh root@www1.cyberciti.biz '/etc/init.d/mysql restart'

(E) Get memory information and store result/output to local file /tmp/memory.status:
$ ssh vivek@www1.cyberciti.biz 'free -m' > /tmp/memory.status

(G) You can also run multiple command or use the pipes, following command displays memory in format of "available memory = used + free memory" :
$ ssh vivek@debian.test.com free -m | grep "Mem:" | awk '{ print "Total memory (used+free): " $3 " + " $4 " = " $2 }'

See how to configure ssh for password less login using public key based authentication.

=> Related: shell script to get uptime, disk usage, cpu usage, RAM usage,system load,etc. from multiple Linux servers and output the information on a single server in a html format.

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{ 18 comments… add one }

  • Amitabh May 14, 2008, 10:23 am

    Hi ,

    Can you please help to show “how to run top command in a remote host” ?

    Thanks,

    Amitabh

  • web designer July 22, 2009, 9:38 am

    I have just put this in a script in a cron job to keep the mysql databases in sync. Great.

  • web design July 22, 2009, 9:42 am

    Hi Amitabh, Have you tried “ssh root@domain.com htop”.

    Im not sure where the output would go but its worth a try if you havent already.

    Lien

  • web design and seo August 4, 2009, 10:07 pm

    Thank you, Ive been trying to do this for weeks

  • Sandy December 24, 2009, 5:42 am

    Hi,

    I am trying to execute the script from my local to remote host.
    ssh sandy “/home/user/san/print_my_lines”

    The scripts works all right but not able to come out of remote host.

    Could you please help me out.

  • Sandy December 24, 2009, 5:44 am

    continue to above post.

    Local host – aaa
    RemoteHost – sandy

  • venkat June 25, 2010, 9:24 pm

    dude…I want to execute the following

    ssh user@server

    it is asking for password….how to give password dynamically?

    • Pramod September 22, 2010, 12:57 pm

      You need to exchange the ssh keys between the remote and your machine from where you are doing this.

  • sarath June 27, 2011, 8:04 am

    Is any additional configurations are required to use ssh in Ubuntu

  • Raj August 26, 2011, 6:04 am

    How can we run a script on a remote machine without passwords?

    When i issue the following command, it is prompting for passoword. Could any one advise on this please ?
    ssh username@hostname df -h

  • Siddhat March 5, 2012, 10:17 am

    Can you please suggest how to check the system uptime for last 1year in Unix envirnment is there any parameter to check with uptime cammand which can show the logs of approximately 1 year

    Warm Regards ,

    Siddhant K

  • saurabh July 6, 2012, 12:34 pm

    hi , can any one tell me hw i can enter the password dynamically

  • Thyagaraj September 27, 2012, 8:56 am

    For all who need password automation:

    There is a package called “sshpass” for password automation, you can search if it’s available in the Ubuntu repository by typing ‘apt-cache search sshpass’.

    You can install ‘sshpass’ by ‘apt-get install sshpass’.

    Using ‘sshpass’:
    sshpass -p remote-password-here ssh -o StrictHostKeyChecking=no remote-user-here@remote-ip-here < /path/to/script
    (or)
    sshpass -p secret ssh -o StrictHostKeyChecking=no root@192.168.1.2 "ls -l"

  • rubence September 22, 2013, 12:44 pm

    hello, how can i execute a script in remote machine keeping the script in local machine

  • rubence September 22, 2013, 12:51 pm

    got it …

    for refrence

    ssh root@remotemachine sh < local_script.sh

  • maonato October 8, 2013, 9:58 am

    hi,, i want to run mu script to a server, the script is in add file
    will this command “ssh -i id_rsa@10.0.103.96 ‘bash -s’ > ~.ssh/authorized_keys
    exit

  • tigerwhat January 20, 2014, 2:12 am

    Anyone have an idea of how to use this in with except/spawn?

  • SS March 24, 2015, 12:24 pm

    Hi,

    How to run a a shell script in server 2 by passing a parameter from server1.

    Regards
    Saran

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