How to get telnet output on PowerShell? - powershell

Question

I thought I could run the command as below on PowerShell.
$output = & echo quit | telnet localhost 22
echo $output
However,
$output has nothing in it.
I'm trying to verify ssh or telnet connection.
Could you please tell me how to get output from above command ?

Answer 1

It is not possible. MS telnet doesn't use stdin/out. See here: C# + telnet process w/ redirected standard streams quits immediately
For redirecting the output of a telnet session you can use the -f logfile argument and then importing it into a variable after you are done with it: $output = get-contents logfile
For sending keycommands to telnet you could use $wshell = new-object -com wscript.shell and then:
start-process telnet -argumentlist "-f w:\tmp\log.txt";
sleep 1;
$wshell.SendKeys("quit{ENTER}")
Yes I know... not what you would expect, but it is the only way afaik with the MS builtin telnet console. If you know any better way, I would be glad to hear about it.
If you only want to check open ports, then why not just query them instead of telnetting? See here.

Answer 2

try this script and add it at start and end of your command to capture every logs
$ipV4 = (Test-Connection -ComputerName (hostname) -Count 1).IPV4Address.IPAddressToString -- this
Start-Transcript -Path .\TraceLogs_$ipV4.txt
<**Add your code here**>
Stop-Transcript
Here $ipV4 will capture the source host and logs will be generated in as file name .\TraceLogs_$ipV4.txt

Answer 3

Trying to adapt this for collecting Telnet output from APC PDUs (reading current load). The specified keys are successfully entered and the output is generated in the telnet session window, but the window doesn't close once the telnet session is ended. It stays open with "Connection to host lost."
I can press any key to close the window, but PS script execution does not continue, so no code following the SendKeys statement is executed.
Am I missing something simple? Code below.
$wshell = new-object -com wscript.shell
start-process telnet -argumentlist "pdu1-a6.domain.local -f c:\temptelnet.log"
sleep 1
$wshell.SendKeys("username{ENTER}password{ENTER}current{ENTER}quit{ENTER}")
$telnetoutput = get-content c:\temptelnet.log
$telnetoutput