I am trying to run a nested ssh -t -t but it won't provide me the environment variables when working with cat and echo.
#!/bin/bash
pass="password\n"
bla="cat <(echo -e '$pass') - | sudo -S su -"
ssh -t -t -t -t jumpserver "ssh -t -t -t -t server \"$bla\" "
I get an output without any variables taken into consideration. (e.g. PS1 does not get shown but commands work fine) The problem is related to cat <(echo -e '$pass') - but this was the way to keep echo alive after providing the password for sudo.
How can i achieve this and get environment variables to get a proper output?
Thanks.
The -tt is enough. Using more -t does not add any more effect and just makes an impression that you have no idea what are you doing.
What is the point of cat <(echo -e) construction? Writing just echo would result in the same, isn't it?
Why to use sudo su? sudo already does all you need, isn't it?
So how can it look in some fashionable manner?
pass="password\n"
bla="echo '$pass' | sudo -Si"
ssh -tt jumpserver "ssh -tt server \"$bla\""
And does it work? Try to debug the commands with -vvv switches to the ssh. It will show you what is actually executed and passed to each other shell.
Related
but needed execute $() in server, it is running before ssh
ssh -t -o StrictHostKeyChecking=no -i "${SSH_KEY}" "${HOST}" "$(command)"
this is a script that I need to run that code on the server
If you run that, it will execute whats inside of the $() before connecting to the server. Then it will send the result to be executed.
I think what you want is do this :
ssh -t -o StrictHostKeyChecking=no -i "${SSH_KEY}" "${HOST}" 'command'
Where command might be something like :
ls -lh | grep someword
Let me know if I am correct.
I'm getting incredibly frustrated here. I simply want to run a sudo command on a remote SSH connection and perform operations on the results I get locally in my script. I've looked around for close to an hour now and not seen anything related to that issue.
When I do:
#!/usr/bin/env bash
OUT=$(ssh username#host "command" 2>&1 )
echo $OUT
Then, I get the expected output in OUT.
Now, when I try to do a sudo command:
#!/usr/bin/env bash
OUT=$(ssh username#host "sudo command" 2>&1 )
echo $OUT
I get "sudo: no tty present and no askpass program specified". Fair enough, I'll use ssh -t.
#!/usr/bin/env bash
OUT=$(ssh -t username#host "sudo command" 2>&1 )
echo $OUT
Then, nothing happens. It hangs, never asking for the sudo password in my terminal. Note that this happens whether I send a sudo command or not, the ssh -t hangs, period.
Alright, let's forget the variable for now and just issue the ssh -t command.
#!/usr/bin/env bash
ssh -t username#host "sudo command" 2>&1
Then, well, it works no problem.
So the issue is that ssh -t inside a variable just doesn't do anything, but I can't figure out why or how to make it work for the life of me. Anyone with a suggestion?
If your script is rather concise, you could consider this:
#!/usr/bin/env bash
ssh -t username#host "sudo command" 2>&1 \
| ( \
read output
# do something with $output, e.g.
echo "$output"
)
For more information, consider this: https://stackoverflow.com/a/15170225/10470287
I'd like to capture the output of an ssh session. However, I first need to ssh twice (from my local computer to the remote portal to the remote server), then run a command and capture the output.
Doing this line-by-line, I would do:
ssh name#remote.portal.com
ssh remote.server.com
remote.command.sh
I have tried the following:
server=remote.server.com ##define in the script, since it varies
sshoutput=$(ssh -tt name#remote.portal.com exec "ssh -tt ${server} echo \"test\"")
echo $sshoutput
I would expect the above script to echo "test" after the final command. However, the outer ssh prompt just hangs after I enter my command and, once I Ctrl+c or fail to enter my password, the inner ssh session fails (I believe since stdout is no longer printed to screen and I no longer get my password prompt).
If I run just the inner command (i.e., without "sshoutput=$(" to save it as a variable), then it works but (obviously) does not capture output. I have also tried without the "exec".
I have also tried saving the inner ssh as a variable like
sshoutput=$(ssh -tt name#portal myvar=$(ssh -tt ${server} echo \"test\"") && echo $myvar)
but that fails because BASH tries to execute the inner ssh before sending it to the outer ssh session (I believe), and the server name is not recognized.
(I have looked at https://unix.stackexchange.com/questions/89428/ssh-twice-in-bash-alias-function but they simply say "more flags required if using interactive passwords" and do not address capturing output)
Thanks in advance for any assistance!
The best-practice approach here is to have ssh itself do the work of jumping through your bouncehost.
result=$(ssh \
-o 'ProxyCommand=ssh name#remote.portal.com nc -w 120 %h %p' \
name#remote.server.com \
"remote.command.sh")
You can automate that in your ~/.ssh/config, like so:
Host remote.server.com
ProxyCommand ssh name#remote.portal.com nc -w 120 %h %p
...after which any ssh remote.server.com command will automatically jump through remote.portal.com. (Change nc to netcat or similar, as appropriate for tools that are installed on the bouncehost).
That said, if you really want to do it yourself, you can:
printf -v inner_cmd '%q ' "remote.command.sh"
printf -v outer_cmd '%q ' ssh name#remote.server.com "$inner_cmd"
ssh name#remote.portal.com bash -s <<EOF
$outer_cmd
EOF
...the last piece of which can be run in a command substitution like so:
result=$(ssh name#remote.portal.com bash -s <<EOF
$outer_cmd
EOF
)
I have a script which starts an ssh-connection.
so the variable $ssh start the ssh connection.
so $SSH hostname gives the hostname of the host where I ssh to.
Now I try to echo something and copy the output of the echo to a file.
SSH="ssh -tt -i key.pem user#ec2-instance"
When I perform a manual ssh to the host and perform:
sudo sh -c "echo 'DEVS=/dev/xvdbb' >> /etc/sysconfig/docker-storage-setup"
it works.
But when I perform
${SSH} sudo sh -c "echo 'DEVS=/dev/xvdb' > /etc/sysconfig/docker-storage-setup"
it does not seem to work.
EDIT:
Also using tee is working fine after performing an ssh manually but does not seem to work after the ssh in the script.sh
The echo command after an ssh of the script is happening on my real host (from where I'm running the script, not the host where I'm performing an ssh to). So the file on my real host is being changed and not the file on my host where I've performed an ssh to.
The command passed to ssh will be executed by the remote shell, so you need to add one level of quoting:
${SSH} "sudo sh -c \"echo 'DEVS=/dev/xvdb' > /etc/sysconfig/docker-storage-setup\""
The only thing you really need on the server is the writing though, so if you don't have password prompts and such you can get rid of some of this nesting:
echo 'DEVS=/dev/xvdb' | $SSH 'sudo tee /etc/sysconfig/docker-storage-setup'
I am trying to update the crontab file of 1000+ systems using a for loop from jump host.
The below doesn't work.
echo -e 'pass365\!\n' | sudo -S echo 'hello' >> /var/spool/cron/root
-bash: /var/spool/cron/root: Permission denied
I do have (ALL) ALL in the sudoers file.
This is another solution;
echo 'pass365\!' | sudo -S bash -c 'echo "hello">> /var/spool/cron/root'
The below worked for me.
echo 'pass365\!' | sudo -S echo 'hello' | sudo -S tee -a /var/spool/cron/root > /dev/null
Problem 1: You are trying to send the password via echo to sudo.
Problem 2: You can't use shell redirection in a sudo command like that.
Between the two of these, consider setting up ssh public key authorization and doing
ssh root#host "echo 'hello' \>\> /var/spool/cron/root"
You may eventually get sudo working but it will be so much more pain than this.