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Wrong CR/LF behavior in ssh.exe #1256
Description
"OpenSSH for Windows" version
7.7.2.0
Server OperatingSystem
FreeBSD 10.4-RELEASE amd64
TERM=cons25r
Client OperatingSystem
Windows 7 x64 russian
TERM=cons25r
What is failing
CR worked as CR+LF, LF are ignored. This leads to multiple output issues in my case.
Background:
The server assumes the historical behavior of the terminal, in which it works as mechanical teletype or typewriter.
One or more of CR should cause the mechanical carriage will be move to the position of the first character of the same line, without scrolling the paper.
Each LF should cause the paper to scroll to the next line, without moving the carriage to anywhere.
Expected output
Server sends 0x0d 0x0d 0x0a and prompt, each time you press Return:
On exit from Midnight Commander, server sends 0x1b 0x5b 0x4b 0x0a 20+ times, for line by line screen cleaning and move cursor to last line:
Actual output
Unwanted blank lines:
The screen is not cleared, prompt is in the second line from upper end:
Activity
dpsenner commentedon Feb 8, 2019
I'm observing an issue that appears to be related to this one when connecting to a linux machine from windows in a powershell console. I.e. after starting the powershell.exe I observe "user@some-host" to be duplicated on the same line:
It appears that the way how
clearandmanattempt to clear the screen does not work out well when done from an ssh shell started in a powershell.Noteworthy, too, is that with the
user@some-host:~$ user@some-host:~$printed it is enough to resize the powershell window to restore it such that it displaysuser@some-host:~$, i.e. by grabbing it with the mouse and increasing or decreasing the width by one column. Decreasing the powershell windows' height does not help, though.vsalvino commentedon Mar 2, 2019
I am also seeing the exact issue that dpsenner reported above. Issue is the same regardless of using any combination of CMD, PowerShell 5.1, or PowerShell 6.1 with Win32-OpenSSH client 7.7 or 7.9.
Also interesting, but probably unrelated, is that ssh.exe seems to always change the cursor size to "small" even it if it set as "large" in PowerShell.
maertendMSFT commentedon Jul 16, 2020
Dustin L. Howett (MSFT) (@DHowett-MSFT) , this appears to be a console issue, can you take a look?
DHowett commentedon Aug 24, 2020
This probably has the same root cause as the login/motd duplication issue that was fixed in PowerShell/openssh-portable#426.
DHowett commentedon Aug 24, 2020
Sorry, I was reading the comments #1256 (comment) and #1256 (comment) which are off-topic for this issue. 😬
This
cons25ris not something that I have ever seen, and I do not expect that it has the right terminfo/termcap behavior for the Windows Console.At the same time, when Win32-OpenSSH is running on windows 7, it does a significant amount of preprocessing before sending output to the console. I'd start debugging there 😄
bagajjal commentedon Mar 30, 2021
For Windows 7, we support only VT100.
From windows10, we have full xterm support from the windows console team.
We are not investing to fix bugs in VT100.