How to run a command
on Remote server without login to server shell prompt ?
By using SSH command, You can run a command on remote
server without login to server shell.
SSH Command Format:
# ssh remoteuser@remotehost remotecommand
Suppose I want to run ls command on remote server pk.testmail.com
parveen@Earth:~$ ssh
root@pk.testmail.com ls
The authenticity of host ' pk.testmail.com
(x.x.x.x)' can't be established.
RSA key fingerprint is
7d:74:91:ed:30:1e:86:0b:69:c9:77:0b:72:0e:ad:4e.
Are you sure you want to continue connecting
(yes/no)? yes
Warning: Permanently added 'pk.testmail.com'
(RSA) to the list of known hosts.
root@pk.testmail.com's password:
anaconda-ks.cfg
downloads
install.log
install.log.syslog
Note : – When we run any command on remote server, by default ssh
will not allocate a pseudoterminal. For using pseudoterminal we have to
use -t option with ssh command as explained below.
parveen@Earth:~$ ssh
-t root@ pk.testmail.com ls
root@pk.testmail.com's password:
anaconda-ks.cfg downloads
install.log install.log.syslog
Connection to pk.testmail.com closed.
Now you can see, Command out put will be same as we run same
command after login to remote server.
To run multiple commands on remote server, use semi-colon
between commands as shown below:
parveen@Earth:~$ ssh
-t root@ pk.testmail.com "ls ; df -h ; date ; cal"
root@pk.testmail.com's password:
anaconda-ks.cfg downloads
install.log install.log.syslog server_invalid_mails_cleanup.sh
Filesystem
Size Used Avail Use% Mounted on
/dev/vda
20G 6.9G 12G 37% /
tmpfs
246M 0 246M 0% /dev/shm
Mon Nov 10 00:52:12 EST 2014
November 2014
Su Mo Tu We Th Fr Sa
1
2 3 4 5 6
7 8
9 10 11 12 13 14 15
16 17 18 19 20 21 22
23 24 25 26 27 28 29
30
Connection to pk.testmail.com closed.
We can also use echo command to run a remotecommand on
remoteserver.
parveen@Earth:~$ echo
"ls" | ssh root@pk.testmail.com
Pseudo-terminal will not be allocated because
stdin is not a terminal.
root@pk.testmail.com's password:
anaconda-ks.cfg
downloads
install.log
install.log.syslog
Note:- We can’t use -t option with ssh command to run
remotecommand using echo command because Pseudo-terminal will not be
allocated because stdin is not a terminal.
Use ssh command with tar command to move a directory of files
between two machines as an alternative to scp command. Example is explained
below:
parveen@Earth:~$ tar
-cvf - images/test1 | ssh root@ pk.testmail.com '(cd /tmp/; tar -xf -)'
images/test1/
images/test1/7
images/test1/6
images/test1/5
images/test1/4
images/test1/9
images/test1/8
images/test1/3
images/test1/2
images/test1/1
root@pk.testmail.com's password:
Now files are uploaded
on Remote server. Check files on remote server as shown below.
[root@pk tmp]# ls -l
images/
total 4
drwxrwxr-x 2 1000 1000 4096 Nov 10 01:02 test1
[root@pk tmp]# ls -l images/test1/
total 0
-rw-rw-r-- 1 1000 1000 0 Nov 10 01:02 1
-rw-rw-r-- 1 1000 1000 0 Nov 10 01:02 2
-rw-rw-r-- 1 1000 1000 0 Nov 10 01:02 3
-rw-rw-r-- 1 1000 1000 0 Nov 10 01:02 4
-rw-rw-r-- 1 1000 1000 0 Nov 10 01:02 5
-rw-rw-r-- 1 1000 1000 0 Nov 10 01:02 6
-rw-rw-r-- 1 1000 1000 0 Nov 10 01:02 7
-rw-rw-r-- 1 1000 1000 0 Nov 10 01:02 8
-rw-rw-r-- 1 1000 1000 0 Nov 10 01:02 9
