Excecuting script running ssh commands in the background - bash

I'm trying to execute this script on a remote server with requiretty enabled in the sudoers file.
#!/bin/bash
value=$(ssh -tt localhost sudo bash -c hostname)
echo $value
If I run the script using $ ./sample.sh & it stays stopped in the background. Only by using fg I can force the script to run. I think the problem is the missing tty for the output, but what can I do?

... what can I do?
You can stty -tostop.

Related

Putty: trying to send multiple commands to remote server but only the first is executed [duplicate]

I want to run multiple commands automatically like sudo bash, ssh server01, ls , cd /tmp etc at server login..
I am using Remote command option under SSH in putty.
I tried multiple commands with delimiter && but not working.
There is a some information lacking in your question.
You say you want to run sudo bash, then ssh server01.
Will sudo prompt for a password in your remote server?
Assuming there is no password in sudo, running bash will open another shell waiting for user input. The command ssh server01 will not be run until that bash shell is exited.
If you want to run 2 commands, try first simpler ones like:
ls -l /tmp ; echo "hi there"
or if you prefer:
ls -l /tmp && echo "hi there"
Does this work?
If what you want is to run ssh after running bash, you can try :
sudo bash -c "ssh server01"
That is probably because the command is expected to be a program name followed by parameters, which will be passed directly to the program. In order to get && and other functionality that is provided by a command line interpreter such as bash, try this:
/bin/bash -c "command1 && command2"
I tried what I suggested in my previous answer.
It is possible to run 2 simple commands in putty separated by a semicolon. As in my example I tried with ls and echo. The remote server runs them and then the session closes.
I also tried to ssh to a remote server that is configured for not asking for a password. In that case, it also works, I get connected to the 2nd server and I can run commands on it. Upon exit, the 2 connections are closed.
So please, let us know what you actually need / want.
You can execute two consecutive commands in PuTTY using a regular shell syntax. E.g. using ; or &&.
But you want to execute ssh server01 in sudo bash shell, right?
These are not two consecutive commands, it's ssh server01 command executed within sudo bash.
So you have to use a sudo command-line syntax to execute the ssh server01, like
sudo bash ssh server01

Exporting ROS Master URI from shell script

I am trying to export ROS_MASTER_URI from a shell script and then launch roscore. In my .sh file I have:
roxterm --tab -e $SHELL -c "cd $CATKIN_WS; $srcdevel; export ROS_MASTER_URI='http://locahost:1234'; roscore -p 1234"
When I do this, however, I get the following error in the roscore tab:
WARNING: ROS_MASTER_URI [http://locahost:1234] host is not set to this machine.
When I echo the ROS_MASTER_URI in this tab, it says that it is localhost:1234, which is correct. When I manually execute these commands, it works correctly and roscore launches without any issues. I am not sure why it does not work when launched from a bash file.
It was just a typo- missed the l in localhost. All working now.

BASH instead of CSH while running Commands on a Remote Linux Server over SSH

I would like to run a command on a remote server using ssh, under bash, while my default session is csh.
minimal example (true command is more complex and is generated by my IDE remote debugger):
ssh hostname 'ls | head'
I don't have admin privileges. Trying chsh -s /bin/bash results with an error chsh: cannot lock /etc/passwd; try again later.
I tried adding to .cshrc the following
setenv SHELL /bin/bash
exec /bin/bash --login
but it freezes the console when sending the command through ssh (while regular ssh works)
Any idea how to solve that?
NOTE: I must have a solution that would configure the host, because I don't have access to the ssh command which is generated automatically by the debugger of my IDE. On the IDE I can only set the host name and port number. (EDIT) Therefore solutions like ssh hostname '/bin/bash -c "ls | head"' wont apply
EDIT2:
Actual command shown by IDE (again, I can't edit it):
ssh://username#localhost:2213/home/lab/username/anaconda2/envs/tf_011b/bin/python -u /specific/a/home/cc/cs/username/.pycharm_helpers/pydev/pydevd.py --multiproc --qt-support --client '0.0.0.0' --port 41823 --file /home/lab/username/remote_py/nlteach/show_attend_and_tell/train_saat_classifier.py --train_dir=/home/lab/username/nlteach/output/train/d=cub/imSD=11%imSP=rnd%tcSP=cvpr16/CSat/res50%lr0_02LrDTexpLrDc0_938OrmspWDc0/emb=512%ldTrn=0%nU=512%noHid=1%lr=0_02%lrDT=fix%lrDc=1%o=rmsp/
I am not sure why, but on a bash enabled server it works, while it fails on the csh host.
Thanks!
Invoke bash on the remote side, telling it what commands to run:
ssh hostname '/bin/bash -c "ls | head"'
If the command is too complicated (eg because of quotation mark escaping), then write your commands to a script, copy the script, then run the script:
scp script.bash hostname:/tmp/
ssh hostname '/bin/bash /tmp/script.bash'

run ssh script into ubuntu instance do something, when exit, stay in ubuntu

I am running a very simple script that will ssh into a remote ubuntu instance, move around the directory structure execute a few things, then I want the prompt to stay in Ubuntu. When the script ends, in ends back at the local prompt. How do I make modify the script so that it finishes with the remote prompt?
local$ ssh -i xxx.pem ubuntu#xxx.ap-region.compute.amazonaws.com \
"cd virtualenv; ls -lh;"
There are two things needed to be added to your commandline:
The bash command in the end starts the bash shell (you can start any other you want)
The -t switch will make sure the remote server will allocate you TTY and your shell will work as expected:
local$ ssh -t -i xxx.pem ubuntu#xxx.ap-region.compute.amazonaws.com \
"cd virtualenv; ls -lh; bash"

sending script over ssh using ruby

I'm attempting to write a bash script in ruby that will start a Resque worker for one of my apps.
The command that I generate from the params given in the console looks like this...
command = "ssh user##{#ip} 'cd /path/to/app; bundle exec rake resque:work QUEUE=#{#queue}&'"
`command`
The command is interpolated correctly and everything looks great. I'm asked to input the password for the ssh command and then nothing happens. I'm pretty sure my syntax is correct for making an ssh connection and running a line of code within that connection. ssh user#host 'execute command'
I've done a simpler command that only runs the mac say terminal command and that worked fine
command = "ssh user##{#ip} 'say #{#queue}'"
`command`
I'm running the rake task in the background because I have used that line once inside ssh and it will only keep the worker alive if you run the process in the background.
Any thoughts? Thanks!
I figured it out.
It was an rvm thing. I need to include . .bash_profile at the beginning of the scripts I wanted to run.
So...
"ssh -f hostname '. .bash_profile && cd /path/to/app && bundle exec rake resque:work QUEUE=queue'" is what I needed to make it work.
Thanks for the help #Casper
Ssh won't exit the session until all processes that were launched by the command argument have finished. It doesn't matter if you run them in the background with &.
To get around this problem just use the -f switch:
-f Requests ssh to go to background just before command execution. This is
useful if ssh is going to ask for passwords or passphrases, but the user
wants it in the background. This implies -n. The recommended way to start
X11 programs at a remote site is with something like ssh -f host xterm.
I.e.
"ssh -f user##{#ip} '... bundle exec rake resque:work QUEUE=#{#queue}'"
EDIT
In fact looking more closely at the problem it seems ssh is just waiting for the remote side to close stdin and stdout. You can test it easily like this:
This hangs:
ssh localhost 'sleep 10 &'
This does not hang:
ssh localhost 'sleep 10 </dev/null >/dev/null &'
So I assume the last version is actually pretty closely equivalent to running with -f.

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