Connecting to a Linux Machine via SSH

[xav.vijay]

Hi friends

I am trying to connect to a Linux machine from a Windows PC. I used to do it thru TELNET, but now I want to use SSH for better security. I tried with PYSSH, but I am going nowhere with it... Parmaiko is not working in Windows... Is there any way this can be done? I just want python to login, issue a command, get the output & then log back out...

Thanks in advance....

[shanenin]

I just installed the pyssh module, it does not really have any good examples to follow. If I figure someting out I will let you know.

[xav.vijay]

I have found a way to SSH to a *IX machine... I tried it with Linux, AIX & Solaris Machines... it works fine..

I downloaded a command line version of PUTTY, called as PLINK. Its a .EXE file.

when executed from the command line

c:\plink username@192.168.0.1 -pw <password> <command to be executed in server>

it just runs the required command & displays the output in our local machine..

So by using os.popen(), we can execute it & fetch the output for further processing....

[shanenin]

Thanks for the update :-)

this could come in handy. I am always writing scripts that need to connect my windows and linux boxes. Using ssh I could use this to communicate with computers both on my intranet and also remote computers on the internet.

[ms_melagiri]

You can use the following code snippet to connect thru ssh and also do scp.

# Login to ABC Machine via SSH
child = pexpect.spawn('ssh -l %s %s'%(ABCusername, ABChostname))
i = child.expect([pexpect.TIMEOUT, SSH_NEWKEY, COMMAND_PROMPT, '(?i)password'])
if i == 0: # Timeout
print 'ERROR! could not login with SSH. Here is what SSH said:'
print child.before, child.after
print str(child)
sys.exit (1)
if i == 1: # In this case SSH does not have the public key cached.
child.sendline ('yes')
child.expect ('(?i)password')
if i == 2:
# This may happen if a public key was setup to automatically login.
pass
if i == 3:
child.sendline(ABCpassword)
# Now we are either at the command prompt or
# the login process is asking for our terminal type.
i = child.expect ([COMMAND_PROMPT, TERMINAL_PROMPT])
if i == 1:
child.sendline (TERMINAL_TYPE)
child.expect (COMMAND_PROMPT)

# Set command prompt to something more unique.

COMMAND_PROMPT = "\[PEXPECT\]\$ "
child.sendline ("PS1='[PEXPECT]\$ '") # In case of sh-style
i = child.expect ([pexpect.TIMEOUT, COMMAND_PROMPT], timeout=10)
if i == 0:
print "# Couldn't set sh-style prompt -- trying csh-style."
child.sendline ("set prompt='[PEXPECT]\$ '")
i = child.expect ([pexpect.TIMEOUT, COMMAND_PROMPT], timeout=10)
if i == 0:
print "Failed to set command prompt using sh or csh style."
print "Response was:"
print child.before
sys.exit (1)

# Now you can do scp as follows:

child.sendline('scp ~/sample.txt %s@%s:/sample.txt'%(XYZusername, XYZhostname))
i = child.expect([pexpect.TIMEOUT, SSH_NEWKEY, COMMAND_PROMPT, '(?i)password'])
if i == 0: # Timeout
print 'ERROR! could not copy with SCP. Here is what SCP said:'
print child.before, child.after
print str(child)
sys.exit (1)
if i == 1: # In this case SSH does not have the public key cached.
child.sendline ('yes')
child.expect ('(?i)password')
if i == 2:
# This may happen if a public key was setup to automatically login.
pass
if i == 3:
child.sendline(XYZpassword)
child.expect(COMMAND_PROMPT)
print child.before

### All u r doing is; connecting to a machine called ABC and from there, u r doing scp to any required machine XYZ.

### I hope it helps u.

[xav.vijay]

Thanks ms_melagiri ...

I will use this code my future implementations....