SSH to Run Command on a Remote Machine..

SSH to Run Command on a Remote Machine..

SSH provides wounder facility to run linux command on remote machine, provided that you have SSH access to that machine…

  • We can use this feature of SSH for troubleshooting purpose… for example suppose there is “logout” command in your “.bashrc” file of remote user. In this case you will not get ssh access until you remove this “logout” command from “.bashrc” file of remote user. This can be done remotely by using SSH..

1] I am login on machine ‘IndianGNU.org’ and trying to login to ‘192.168.0.1’ ie ‘Remote’ machine.. but it immediately logout. see below….

root@IndianGNU.org:/home/arun.bagul# ssh arun.bagul@192.168.0.1
arun.bagul@192.168.0.1’s password:
Last login: Sun Jan 20 18:49:29 2008 from 192.168.0.5
Connection to 192.168.0.1 closed.
root@IndianGNU.org:/home/arun.bagul#

2] This is happening because there is ‘logout’ command added in ‘.bashrc’ file of arun.bagul‘s profile on ‘192.168.0.1’

3] How to check this ‘.bashrc’ file on ‘192.168.0.1’ –

root@IndianGNU.org:/home/arun.bagul# ssh arun.bagul@192.168.0.1 ‘tail /home/arun.bagul/.bashrc’
arun.bagul@192.168.0.1’s password:
if [ -f /etc/bash_completion ]; then
. /etc/bash_completion
fi

######

## ‘logout’ command which will terminate your session just after login.
#You will not get any access via SSH
logout

root@IndianGNU.org:/home/arun.bagul#

4] How to remove this ‘logout’ command from remote file by ssh

root@IndianGNU.org:/home/arun.bagul# ssh arun.bagul@192.168.0.1 ‘sed -i “s/logout/#welcome/g” /home/arun.bagul/.bashrc’
arun.bagul@192.168.0.1’s password:
root@IndianGNU.org:/home/arun.bagul#

5] Check now –

root@IndianGNU.org:/# ssh arun.bagul@192.168.0.1 ‘tail /home/arun.bagul/.bashrc’
arun.bagul@192.168.0.1’s password:
if [ -f /etc/bash_completion ]; then
. /etc/bash_completion
fi

######

## ‘#welcome’ command which will terminate your session just after #login.
#You will not get any access via SSH
#welcome

root@IndianGNU.org:/home/arun.bagul#

6] Now try to login on 192.168.0.1′ with user name ‘arun.bagul’ –

root@IndianGNU.org:/home/arun.bagul# ssh arun.bagul@192.168.0.1
arun.bagul@192.168.0.1’s password:
Last login: Sun Jan 20 18:39:15 2008 from 192.168.0.5
arun.bagul@Remote:~$

7] Other uses of ssh for running remote command –

root@IndianGNU.org:/home/arun.bagul# ssh arun.bagul@192.168.0.1 ‘df -h’
arun.bagul@192.168.0.1’s password:
Filesystem Size Used Avail Use% Mounted on
/dev/hda2 79G 26G 50G 34% /
varrun 1009M 108K 1009M 1% /var/run
varlock 1009M 8.0K 1009M 1% /var/lock
udev 1009M 104K 1009M 1% /dev
devshm 1009M 0 1009M 0% /dev/shm
/dev/hda5 56G 42G 11G 81% /backup
/dev/hda1 361M 27M 315M 8% /boot
/dev/hda6 9.2G 8.6G 180M 98% /var
root@IndianGNU.org:/home/arun.bagul#
** List mounted partion –

root@IndianGNU.org:/home/arun.bagul# ssh root@192.168.0.8 ‘mount’
root@192.168.0.8’s password:
/dev/hda3 on / type ext3 (rw)
proc on /proc type proc (rw)
sysfs on /sys type sysfs (rw)
devpts on /dev/pts type devpts (rw,gid=5,mode=620)
/dev/hda2 on /boot type ext3 (rw)
tmpfs on /dev/shm type tmpfs (rw)
/dev/hda7 on /usr type ext3 (rw)
/dev/hda6 on /var type ext3 (rw)
none on /proc/sys/fs/binfmt_misc type binfmt_misc (rw)
/usr/tmpDSK on /tmp type ext3 (rw,noexec,nosuid,loop=/dev/loop0)
/tmp on /var/tmp type none (rw,noexec,nosuid,bind)
sunrpc on /var/lib/nfs/rpc_pipefs type rpc_pipefs (rw)

root@IndianGNU.org:/home/arun.bagul#
Regards,

Arun Bagul

Similar Posts:

Be Sociable, Share!

Leave a Reply

Your email address will not be published. Required fields are marked *