Ssh multiple hops to execute commands with arguments Post: 302922929

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Top Forums Shell Programming and Scripting Ssh multiple hops to execute commands with arguments Post 302922929 by chiensh on Wednesday 29th of October 2014 08:04:52 AM

10-29-2014

Registered User

Ssh multiple hops to execute commands with arguments

Hi

I need to write a script to ssh through several hops (e.g. HostA-HostB-HostC-HostD), where Host A does not have direct assess to HostC ; HostB cannot access HostD directly.

when I ssh 3 hops and run command with arg1, arg2 and redirect the output to a file, e.g.
HostA> ssh -t HostB ssh -t HostC ssh HostD command arg1 arg2 > output.txt

but it doesn't work as expect it does not pass 2nd argument to command and the output file will be written in HostC, instead of in HostD as expected.

I did some tests to see if quotes or double quotes pairs helps, e.g
(Test 1)

Code:

HostA> ssh -t HostB ssh -t HostC  ssh  HostD  hostname
HostD
Connection to  HostC  closed.
Connection to  HostB  closed.

(Test 2)

Code:

HostA> ssh -t HostB ssh -t HostC  ssh  HostD  hostname;hostname
HostD
Connection to  HostC  closed.
Connection to  HostB  closed.
HostC

(Test 3)

Code:

HostA> ssh -t HostB ssh -t HostC  ssh  HostD  "hostname;hostname"
HostD
Connection to  HostC  closed.
HostB
Connection to  HostB  closed.

(Test 4)

Code:

HostA> ssh -t HostB ssh -t HostC  "ssh HostD   hostname;hostname"
HostD
Connection to  HostC  closed.
Connection to  HostB  closed.
HostB

(Test 5)

Code:

HostA> ssh -t HostB "ssh -t HostC  ssh HostD   hostname;hostname"
HostD
Connection to  HostC  closed.
Connection to  HostB  closed.
HostB

(Test 6)

Code:

HostA> ssh -t HostB ssh -t HostC  ssh HostD   hostname > test.txt
Connection to HostB closed 
(in HostA)

HostA> cat test.txt 
HostD
Connection to HostD closed.
Connection to HostC closed.

(Test 6)

Code:

HostA> ssh -t HostB ssh -t HostC  ssh HostD   hostname > test.txt
Connection to HostB closed 
(in HostA)

HostA> cat test.txt 
HostD
Connection to HostC closed.

(Test 7)

Code:

HostA> ssh -t HostB ssh -t HostC  ssh HostD   "hostname > test.txt"
Connection to HostC closed
Connection to HostB closed 
(in HostB)

HostB> cat test.txt 
HostD

(Test 8)

Code:

HostA> ssh -t HostB ssh -t HostC  "ssh HostD   hostname > test.txt"
Connection to HostC closed
Connection to HostB closed 
(in HostB)

HostB> cat test.txt 
HostD

(Test 9)

Code:

HostA> ssh -t HostB "ssh -t HostC  ssh HostD   hostname > test.txt"
Connection to HostC closed
Connection to HostB closed 
(in HostB)

HostB> cat test.txt 
HostD

(Test 10)

Code:

HostA> ssh -t HostB "ssh -t HostC  ssh HostD   'hostname > test.txt' "
Connection to HostC closed
Connection to HostB closed 
(in HostC)

HostC> cat test.txt 
HostD

(Test 11)

Code:

HostA> ssh -t HostB "ssh -t HostC  'ssh HostD   hostname > test.txt' "
Connection to HostC closed
Connection to HostB closed 
(in HostC)

HostC> cat test.txt 
HostD

(Test 11)

Code:

HostA> ssh -t HostB "ssh -t HostC  'ssh HostD   "hostname > test.txt" ' "
Connection to HostB closed 
(in HostA)

HostA> cat test.txt 

bash: -c: line 0: unexpected EOF while looking for matching `''
bash: -c: line 1: syntax error: unexpected end of file

After these tests, I still cannot find the logics of passing arguments correctly in ssh, can anyone help how to get it work correctly?

Thanks!

Rgds,
Dominic

Last edited by Corona688; 10-29-2014 at 02:58 PM..

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