I was provided a tool to do a SSH to a remote host. The remote host is a new docker to be created. I was trying to understand if there are commands being executed right after the SSH (i.e. probably using ssh -t <some commands>).
It seems like the .bash_history does not include those cmds. In such case, what else can I do to figure out what cmds being executed right after my login? Thank you.
To find out the actual commands that are executed, you could add "set -v" or "set -x" to the shell initialization file(s) on the system you are ssh-ing to.
See man bash (the "INVOCATION" section) to find out which files will executed so that you can figure out which file to add the "set" command to.
You will probably want to do that temporarily ... because the output is verbose.
Another approach would be to configure sshd to set the logging level to DEBUG and see what commands are requested. However, note that sshd DEBUG logging is a user privacy violation.
If you are trying to do this kind of stuff to find out what is happening on the first "boot" of a docker instance, try putting the (temporarily) config changes into the docker image that you are starting.
The bash history only contains command lines that are submitted to the shell via a shell command prompt.
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I want to ssh from my local linux computer into a specific directory on a windows 10 remote. The shell that is used on the remote is git bash. I don't want to keep changing the directory every time I log into my remote using ssh.
for linux remotes this is easily done using something like this:
ssh -t user#x.x.x.x "cd /targetDir ; \$SHELL --login"
The question is how can the same thing be achieved for Windows 10 remotes? If nothing else works I would also accept changing the default entry point in git bash for any ssh sessions on the remote.
Please note that I am not looking for help setting up ssh (already works). I just want to jump right into a specific directory when a session is started.
I was able to figure this thing out myself. The following command gets the job done. Using double and single quotes together is required to make it work (in no particular order).
ssh -t user#x.x.x.x "'cd /targetDir ; bash'"
My environment contains clusters with multiple hosts in each cluster and as such I tend to run similar or equivalent commands on the hosts in such a cluster.
Sometimes, I am ssh-ed into a cluster host and remember that I had run a certain command on another host in this cluster but I can't remember which host I ran it on, however I need to run that command again.
Since every host in the cluster has its own .bash_history, I have to log in to each and every one of them and look through the .bash_history file to locate that command.
However, if I could use one .bash_history file for all hosts in the cluster (e.g. named .bash_history.clusterX) then I would be able to search the command in the bash history (with CTRL+R) and execute it.
Is that possible?
In my setup shared home directory (via nfs, etc.) is not an option.
Another approach is to leave the relevant commands to execute in an executable file ('ssh_commands') in the home folder of each remote user on each machine.
Those ssh_commands will include the commands you need to execute on each server whenever you open an SSH session.
To call that file on each SSH session:
ssh remoteUser#remoteServer -t "/bin/bash --init-file <(echo 'source ssh_commands')"
That way, you don't have to look for the right commands to execute, locally or remotely: your SSH session opens and execute right away what you want.
This question has a good answer for how to put multiple command in an alias for bash.
But how would you do it in the case where you first need to ssh into a server, then do something like change a directory and then launch jupyter notebook?
I tried something like:
alias shortcut='ssh user#server -p 1234 -L 5678:localhost:91011; cd ~/somedir; jupyter notebook --ip=127.0.0.1
Maybe it's because my ssh requires me to type in a password, the last 2 commands aren't being executed.
There are some possible improvements for further convenience, if allowed by the system configuration.
If your need include executing a series of commands on the remote host, and you need to repeat this often, it's reasonable to put the commands in their own shell script and place it on the remote host.
For example in this case the script could be just
#!/bin/sh
cd ~/somedir && jupyter notebook --ip=127.0.0.1
Saving them in a file, add execution bit to it, and you can start the session like ssh user#server -p 1234 -L 5678:localhost:91011 path/to/script.sh
This is touched in this question but my preferred way is the low-score one about putting the script on remote -- I'd like to have each resource reside where they belong.
There's also the problem about what you want to do after starting the session. It seems the command is to start a server process that runs the Jupyter web service. If you just want to stay in the SSH session while monitoring the server, then the simple command should suffice. But if you want to keep the server in the background and log the output (and likely leave the SSH session for now) it's possible to run the server with nohup and redirect its output, by putting in the script something like
nohup jupyter notebook --ip="127.0.0.1" >> stdout.log 2>> stderr.log &
echo "$!" > jupyter-notebook.pid
The second command saves the PID in the file so it'll be easier to check or terminate it later without manually searching for the background process.
I have a fancy prompt working well on my local machine. However, I'm logging to multiple machines, on different accounts via ssh. I would love to have my prompt synchronized everywhere by ssh command itself.
Any idea how to get that? In many cases I'm accessing machines using root account and I can't change permanently any settings there. I want the prompt synchronized.
In principle this is just setting variable PS1.
Try this :
ssh -l root host -t "bash --rcfile /path/to/special/bashrc"
maybe /path/to/special/bashrc can be /tmp/myrc by example
When I try to use an ssh command in a shell script, the command just sits there. Do you have an example of how to use ssh in a shell script?
Depends on what you want to do, and how you use it. If you just want to execute a command remotely and safely on another machine, just use
ssh user#host command
for example
ssh user#host ls
In order to do this safely you need to either ask the user for the password during runtime, or set up keys on the remote host.
First, you need to make sure you've set up password-less (public key login). There are at least two flavors of ssh with slightly different configuration file formats. Check the ssh manpage on your system, consult you local sysadmin or head over to How do I setup Public-Key Authentication?.
To run ssh in batch mode (such as within a shell script), you need to pass a command you want to be run. The syntax is:
ssh host command
If you want to run more than one command at the same time, use quotes and semicolons:
ssh host "command1; command2"
The quotes are needed to protect the semicolons from the shell interpreter. If you left them out, only the first command would be run remotely and all the rest would be run on the local machine.
You need to put your SSH public key into the ~/.ssh/authorized_keys file on the remote host. Then you'll be able to SSH to that host password-less.
Alternatively you can use ssh-agent. I would recommend against storing the password in the script.
You can use expect command to populate the username/password info.
The easiest way is using a certificate for the user that runs the script.
A more complex one implies adding to stdin the password when the shell command asks for it. Expect, perl libraries, show to the user the prompt asking the password (if is interactive, at least), there are a lot of choices.