I have authenticated a server using authorized_keys push so I could run command ssh 192.168.1.101 from my system and could connect via server.
Now, I tried with library , It didn't worked for me
Net::SSH.start("192.168.1.209",username) do |ssh| #output=ssh.exec!("ls -l") end
as, This required username field. I want without username.
So , I tried this
system('ssh 192.168.1.209 "ls -l"')
It run the command for me. But I want the output in a variable like #output in first example. Is there any command any gem or any way by which I could get the solution ?
Any ssh connection requires a username. The default is either your system account name or whatever's specified in .ssh/config for that host you're connecting to.
Your current username should be set as ENV['USER'] if you need to access that.
If you're curious what username is being used for that connection, try finding out with ssh -v which is the verbose mode that explains what's going on.
you can pass parameters into %x[] as follows:
1. dom = ‘www.ruby-rails.in‘
2. #whois = %x[whois #\{dom\}]
Backquotes works very similar to "system" function but with important difference. Shell command enclosed between the backquotes is executed with standard output as result.
So, following statement should execute ssh 192.168.1.209 "ls -l" and puts directory files listing into #output variable:
#output = `ssh 192.168.1.209 "ls -l"`
Related
These three lines of code require authentication twice. I don't yet have password-less authentication set up on this server. In fact, these lines of code are to copy my public key to the server and concatenate it with the existing file.
How can I re-write this process with a single ssh command that requires authentication only once?
scp ~/local.txt user#server.com:~/remote.txt
ssh -l user user#server.com
cat ~/remote.txt >> ~/otherRemote.txt
I've looked into the following possibilities:
command sed
operator ||
operator &&
shared session: Can I use an existing SSH connection and execute SCP over that tunnel without re-authenticating?
I also considered placing local.txt at an openly accessible location, for example, with a public dropbox link. Then if cat could accept this as an input, the scp line wouldn't be necessary. But this would also require an additional step and wouldn't work in cases where local.txt cannot be made public.
Other references:
Using a variable's value as password for scp, ssh etc. instead of prompting for user input every time
https://superuser.com/questions/400714/how-to-remotely-write-to-a-file-using-ssh
You can redirect the content to the remote, and then use commands on the remote to do something with it. Like this:
ssh user#server.com 'cat >> otherRemote.txt' < ~/local.txt
The remote cat command will receive as its input the content of ~/local.txt, passed to the ssh command by input redirection.
Btw, as #Barmar pointed out, specifying the username with both -l user and user# was also redundant in your example.
I am trying to login to Server B from Server A and perform simple UNIX commands on Server B using a shell script. The code is as follows. But ls -al is displaying the result of Server A and not the one that is logged on to i.e Server B. Any inputs are highly appreciated. Thanks
#!/bin/bash
clear
sshpass -p password ssh hostname
ls -al
exit
When the shell interprets a script file, it creates a child process to
execute each command line. So, the command lines after sshpass -p password ssh hostname are not actually executed inside the ssh
session to hostname, but in the host where the bash instance is
running.
To achieve what you want, you can check ssh(1) usage line and note that there is a [command] argument, that says:
If command is specified, it is executed on the remote host instead
of a login shell.
So, one way to do it is sshpass -p password ssh hostname ls -la. Another way which can provide some more flexibility is:
#!/bin/bash
clear
cat | sshpass -p password ssh hostname <<EOF
ls -la
EOF
Which would make ssh start a login shell in the remote host and pass
to its stdin the lines provided in the Here Document. The remote
shell would then interpret those strings as commands and execute them.
If you just want to run ls -al on the remote server, put it on the same line as the ssh command like
sshpass -p password ssh hostname ls -al
it will automatically exit when it gets to the end of the command so you don't need to put exit
Also, if you're going to be doing this and don't want to interactively enter the password, you might want to look at sharing public/private keys and using that so it won't ever ask for a password (unless you password protect your private key)
Is it possible to display the local user on remote host?
eg.:
local_user#ownpc$ ssh remote_user#server
then
echo $some_variable_containing_local_user
that results local_user
Purpose: I have a very limited read access to a UNIX server, i'd like to perform scp from remote to local over the current ssh session. Performed via a shell script, regardless of who logged in. (without any additional installs or local variable modifications)
Ps.: I am not looking for scp ssh:user#host/folder/file /home/user/folder
Thank you!
Using an unquoted here-doc allows local variables to be expanded before passing the commands to ssh
local_user#ownpc$ ssh remote_user#server <<END
echo you are $USER
END
should output
you are local_user
That may give you a basis to script your remote actions in the here-doc.
I'm not 100% clear on your situation but both of these methods work for me:
ssh remote_user#remote_host whoami
and
ssh remote_user#remote_host 'echo $USER'
The first executes "whoami" on the remote host while the second echos out what $USER is set to in the remote shell. I'm a little surprised the second one works because often ssh remote executing does not start a shell but it appears to work anyway.
I am trying to automate my server provisioning process using chef. Since I don't want to run chef as root, I need a chef/deployer user. But I don't want to create this user manually. Instead, I want to automate this step. So I took a shot at scripting it but ran into an issue:
The problem is that if I run
>ssh root#123.345.345.567 '/bin/bash -e' < ./add_user.sh
where add_user contains
//..if the username doesnt exist already
adduser $USERNAME --gecos ''
I never see the output or the prompts of the command.
Is there a way to run interactive commands in this way?
Is there a better way to add users in an automated fashion?
Try this:
ssh -t root#<ipaddress> adduser $USERNAME --gecos
Not sure why you have a $ in the IP address in your original example - that's likely to cause ssh to fail to connect, but since you didn't indicate that sort of failure, I'm assuming that's just a typo.
Since add_user.sh is just a simple command, there's no need for the added complexity of explicitly running bash or the redirection, just run the adduser command via ssh.
And lastly, since $USERNAME is likely defined on the local end, and not on the remote end, even if you could get your original command to "do what you said", you'd end up running adduser --gecos on the remote end, which isn't what you intended.
Try using :
ssh -t root#$123.345.345.567 '/bin/bash -e' < ./add_user.sh
instead.
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.