I want to use rsync to my remote server for which I have SSH access. I use the following command:
rsync -e 'ssh -p 22222' -rtz --delete content_dir/ user#example.com:/home/user/public_html
After entering the command, it asks for the password for the remote location. When I type it, it exits with the message,
stdin: is not a tty
How do I supply the password to rsync? The method suggested should also work when I use it in a shell script.
You need to add:
[ -z "$PS1" ] && return
to the beginig of .bashrc that is located in your home dir.
The password is being accepted here, as you've stated yourself the operation does happen.
The error message "stdin: is not a tty" is due to something in the startup script on your server attempting to process an action that should only happen for interactive logins (when you connect with ssh direct to the server, etc).
[ -z "$PS1" ] && return solves the problem but it checks whether the prompt string length equals to zero and if it does then exits. Although $PS1 will not be set in a non-interactive shell, $PS1 being of zero length doesn't ultimately mean that the shell is not interactive.
Better approach is to check the shell's current options using $-. For example [[ $- != *i* ]] && return.
In case a simple return doesn't do the job, here's another approach taken from this blog article:
if `tty -s`; then
mesg n
fi
tty -s checks if there's a TTY attached (the -s tells it to do so silently and just exit with the appropriate return code). tty returns the tty attached (e.g. "/dev/pts/1"). This should be safer than checking some shell variable ;)
mesg controls the write access to your terminal (msg n disallows writing to the (in our case non-existing) terminal), and thus requires one to be present.
On some systems (in my case Debian Jessie, but there are also reports on Ubuntu) mesg n1 is set unconditionally in either ~/.bashrc or ~/.profile. So if it exists that way, this might be the culprit.
As with the other examples, you can of course make that a one-liner: [[ $(tty -s ) ]] && mesg n. And nobody keeps you from combining the two:
if [[ $(tty -s ) ]]; then
mesg n
else
return
fi
Btw: According to the linked article, this fragment should go to the .bashrc of the machine you connect to (the "remote") – so if that's johndoe#somehost, this should be applied at the start of /home/johndoe/.bashrc on somehost. In my case I only got rid of the message after having applied this change on the "calling host" as well.
PS: Also check the .profile if it has a stand-alone msg n command (it did in my case). If it does, wrap it there.
1: mesg n is used to prevent other users on the machine writing to your current terminal device, which per se is a good thing – but not helpful for some rsync job ;)
Related
I need to rsync to a remote server using a non-standard SSH port and 2FA which I use via Authy app. The SSH works with this command:
ssh -2 -p 9999 -i /Users/Me/.ssh/id_rsa user#9.9.9.9
This brings up a "Verification Code" prompt in the shell. Which I enter from Authy, and I'm in.
Given the discussion on this a StackOverflow answers I tried this variation of rsync:
rsync -rvz -e 'ssh -p 9999 -i /Users/Me/.ssh/id_rsa \
--progress /src/ user#9.9.9.9.9:/dest/
(Put here on two lines just for legibility, it's one line in my shell command).
This does bring up the Verification Code prompt, which I enter correctly, but then it produces this error:
protocol version mismatch -- is your shell clean?
(see the rsync man page for an explanation)
rsync error: protocol incompatibility (code 2) at compat.c(185) [sender=3.1.3]
How can I use rsync with 2FA? Many thanks.
Because #JGK mentioned the answer in the comment, adding answer here for posterity. This "is your shell clean" stuff is shown when remote server is echoing some output upon login, which in my case .bashrc indeed was. I've added a conditional to that echo only to apply when the shell login is "interactive", as mentioned in this Server Fault thread, and it works. Just for easier clarity, the IF condition reads as follows:
if echo "$-" | grep i > /dev/null; then
[any code that outputs text here]
fi
Many thanks.
I am using Cygwin on Windows 7 to connect to a unix (RHEL 6) server via SSH. When I do so, X forwarding is not being set correctly:
(Starting from Cygwin xterm on the Windows machine)
> echo $DISPLAY
:0
> ssh -Y myname#rhel.server.com
[enter password]
> echo $DISPLAY
localhost:52.0:0
If I now try to start any windowed process, I get an error message:
> emacs
emacs: Cannot connect to X server localhost:52.0:0.
Check the DISPLAY environment variable or use '-d'.
Also use the 'xhost' program to verify that it is set to permit connections from your machine.
Additional Details
The number that follows 'localhost' (52 in the example above) is different each time I connect.
If I do the following,
> export DISPLAY=localhost:52.0
(that is, I remove the trailing ":0) then this DOES fix the issue, and the window forwarding works just fine.
So the question is: how to fix so that I do not need to manually change the DISPLAY variable with each connection?
A false alarm, much to my embarrassment. Turns out my .profile (that I had borrowed from someone else, as it contained a large quantity of useful customization for our development environment) contained these lines:
export DISPLAY
if [[ -z $DISPLAY ]]; then
DISPLAY=my.machine.addr:0
elif echo $DISPLAY | grep -z -v ':0'; then
DISPLAY=$DISPLAY:0
fi
Lo and behold, commenting out the elif branch solves the problem. May this be a lesson to us all on the dangers of copying someone else's config without knowing what it contains.
I have a script in which I'm meticulously checking return codes for error conditions, so that I can abort early in the event of a failure. One step of this script involves running a command as the root user on another box, via ssh and sudo.
Consider:
ssh $HOST sudo $CMD
echo $?
ssh passes return codes back just fine, but even if $CMD returns a nonzero exit code, sudo still returns 0 after running the command.
How do I capture the return code to $CMD? I'm very partial to its being passed back as ssh's return code, but if there's another simple method which can't be confused by the output of $CMD, I'm all ears.
As it turns out, sudo is passing the return code properly. My test case very likely was overwriting $? with a subsequent execution or conditional test. I normally use a named variable to preserve $? to avoid such things, but there you are.
I am looking for a multiplatform solution that would allow me to check if scp command is available.
The problem is that scp does not have a --version command line and when called without parameters it will return with exit code 1 (error).
Update: in case it wasn't clear, by multiplatform I mean a solution that will work on Windows, OS X and Linux without requiring me to install anything.
Use the command which scp. It lets you know whether the command is available and it's path as well. If scp is not available, nothing is returned.
#!/bin/sh
scp_path=`which scp || echo NOT_FOUND`
if test $scp_path != "NOT_FOUND"; then
if test -x ${scp_path}; then
echo "$scp_path is usable"
exit 0
fi
fi
echo "No usable scp found"
sh does not have a built-in which, thus we rely on a system provided which command. I'm not entirely sure if the -x check is needed - on my system which actually verifies if the found file is executable by the user, but this may not be portable. On the rare case where the system has no which command, one can write a which function here.
How do I execute a command every time after ssh'ing from one machine to another?
e.g
ssh mymachine
stty erase ^H
I'd rather just have "stty erase ^H" execute every time after my ssh connection completes.
This command can't simply go into my .zshrc file. i.e. for local sessions, I can't run the command (it screws up my keybindings). But I need it run for my remote sessions.
Put the commands in ~/.ssh/rc
You can put something like this into your shell's startup file:
if [ -n "$SSH_CONNECTION" ]
then
stty erase ^H
end
The -n test will determine if SSH_CONNECTION is set which happens only when logged in via SSH.
If you're logging into a *nix box with a shell, why not put it in your shell startup?
.bashrc or .profile in most cases.
Assuming a linux target, put it in your .profile
Try adding the command below the end of your ~/.bashrc. It should be exited upon logoff. Do you want this command only executed when logging off a ssh session? What about local sessions, etc?
trap 'stty erase ^H; exit 0' 0
You probably could setup a .logout file from /etc/profile using this same pattern as well.
An answer for us, screen/byobu users:
The geocar's solution will not work as screen will complain that "Must be connected to a terminal.". (This is probably caused by the fact that .ssh/rc is processed before shell is started. See LOGIN PROCESS section from man 8 sshd).
Robert's solution is better here but since screen and byobu open it's own bash instance, we need to avoid infinite recursion. So here is adjusted byobu-friendly version:
## RUN BYOBU IF SSH'D ##
## '''''''''''''''''' ##
# (but only if this is a login shell)
if shopt -q login_shell
then
if [ -n "$SSH_CONNECTION" ]
then
byobu
exit
fi
fi
Note that I also added exit after byobu, since IMO if you use byobu in the first place, you normally don't want to do anything outside of it.