I have a tcl script that calls a lot of functions from bash including ssh. The part I'm struggling with looks like this:
proc connect {where} {
set bash c:/cygwin/bin/bash
catch {exec $bash -c "ssh $where"} result
puts $result
}
connect user#localhost
I get the authentication failed message:
Pseudo-terminal will not be allocated because stdin is not a terminal.
Permission denied, please try again.
Permission denied, please try again.
Permission denied (publickey,password,keyboard-interactive).
I can't figure out how to prompt (either showing the console or a tk window, doesn't really matter) the user for the password so the authentication goes through.
The reason I'm using bash to ssh is because eventually I want to connect to a github with the script (need to prompt for a passkey).
Try this:
puts -nonewline "enter your passphrase: "
flush stdout
gets stdin passphrase
exec $bash -c "ssh $where" << $passphrase
The << argument to exec passes the given value to the command on its stdin
If that doesn't work, you'll have to try Expect, or use a key with no passphrase.
One important alternative (which I advise) is to set up a local key-handling agent (e.g., ssh-agent or pageant) to hold the decrypted key so that your code doesn't need to handle passwords at all. I find that's a much simpler method overall because it stops a lot of code from having to understand anything about passwords (which are harder to handle correctly than you might think…)
Related
I'd like to automate getting diagnostic files from a controller that responds to ssh commands, like e.g.
ssh diag#controller tarred > diags.tgz
Unfortunately, I have to type a password to make the above command go through.
What have I considered to get around that:
using ssh keys: not possible, since I can't login to the controller, it just expects commands and doesn't offer a shell
using ssh-pass package: I don't have admin rights on the machine and can't install packages
using "expect": works to some extent, but the resulting file is corrupted.
Here's the "expect" script I've used:
#!/usr/bin/expect -f
log_user 0
set timeout 300
spawn ssh diag#controller tarred
expect "?assword:"
send "unrealpassword\r"
expect \r\n
log_user 1
expect eof
The script makes sure that only the required output gets stored with the "log_user" commands until eof is encountered.
I've piped this script to a file and that file is corrupted, i.e. it's either too short (because of a timeout?) or too long (?).
Any idea about what goes wrong here.?
So, I've established a connection via ssh to a remote machine; and now what I would like to do is to execute few commands, grab some files and copy them back to my host machine.
I am aware that I can run
ssh user#host "command1; command2;....command_n"
and then close the connection, but how can I do the same without use the aforememtioned syntax? I have a lot of complex commands that has a bunch of quote and characters that would be a mess to escape.
Thanks!
My immediate thought is why not create a script and push it over to the remote machine to have it run locally in a text file? If you can't for whatever reason, I fiddled around with this and I think you could probably do well with a HEREDOC:
ssh -t jane#stackoverflow.com bash << 'EOF'
command 1 ...
command 2 ...
command 3 ...
EOF
and it seems to do the right thing. Play with your heredoc to keep your quotes safe, but it will get tricky. The only other thing I can offer (and I totally don't recomend this) is you could use a toy like perl to read and write to the ssh process like so:
open S, "| ssh -i ~/.ssh/host_dsa -t jane#stackoverflow.com bash";
print S "date\n"; # and so on
but this is a really crummy way to go about things. Note that you can do this in other languages.
Instead of the shell use some scripting language (Perl, Python, Ruby, etc.) and some module that takes care of the ugly work. For example:
#!/usr/bin/perl
use Net::OpenSSH;
my $ssh = Net::OpenSSH->new($host, user => $user);
$ssh->system('echo', 'Net::Open$$H', 'Quot%$', 'Th|s', '>For', 'You!');
$ssh->system({stdout_file => '/tmp/ls.out'}, 'ls');
$ssh->scp_put($local_path, $remote_path);
my $out = $ssh->capture("find /etc");
From here: Can I ssh somewhere, run some commands, and then leave myself a prompt?
The use of an expect script seems pretty straightforward... Copied from the above link for convenience, not mine, but I found it very useful.
#!/usr/bin/expect -f
spawn ssh $argv
send "export V=hello\n"
send "export W=world\n"
send "echo \$V \$W\n"
interact
I'm guessing a line like
send "scp -Cpvr someLocalFileOrDirectory you#10.10.10.10/home/you
would get you your files back...
and then:
send "exit"
would terminate the session - or you could end with interact and type in the exit yourself..
I want to write a simple bash script using ncat to open a connection to a ISP and its port.
The first command would be:
nc address port
Upon doing this, I am prompted first to provide a username. I must hit ENTER, and then I will be prompted to provide a password and then I must hit ENTER again.
After this, I want to open a Terminal process window. Can anyone point me to sufficient resources for this type of scripting?
I know the username and password already, but I'm not too sure how to work around the fact that I must provide it and then hit enter. I'm also unsure how to open a new Terminal proceses.
Thanks in advance!
Check out expect script
Expect
Example:
# Assume $remote_server, $my_user_id, $my_password, and $my_command were read in earlier
# in the script.
# Open a telnet session to a remote server, and wait for a username prompt.
spawn telnet $remote_server
expect "username:"
# Send the username, and then wait for a password prompt.
send "$my_user_id\r"
expect "password:"
# Send the password, and then wait for a shell prompt.
send "$my_password\r"
expect "%"
# Send the prebuilt command, and then wait for another shell prompt.
send "$my_command\r"
expect "%"
# Capture the results of the command into a variable. This can be displayed, or written to disk.
set results $expect_out(buffer)
# Exit the telnet session, and wait for a special end-of-file character.
send "exit\r"
expect eof
The secret lies in the HEREDOC
You can solve this problem with something akin to:
$ command-that-needs-input <<EOF
authenticate here
issue a command
issue another command
EOF
Look at the link I provided for here documents - it includes support for variable substitution and lots of other useful things. Enjoy!
This is the first time I am writing a shell script. I tried to do as much research as I can to avoid dumb/repetitive question. Please excuse if its repeat/dumb question.
I have a shell script which connects to remote linux machine and runs scripts there. I am using 'expect' to spawn a ssh connection and to issue commands to trigger the job. However, I am having issues while closing the connection after completing the job.
This is my script:
set prompt "(%|#|\\$|%\]) $"
expect -c 'spawn ssh $UN#$STAGE ;
expect password ; send "$PASS \n";
expect -regexp "$PROMPT"; send "./settings.$UN.sh > settings_log.txt \n";
interact'
This script successfully runs the script file for me ($UN and $STAGE parameters are input to the script. I omitted that here for simplicity). However, this leaves me with an open connection.
I tried to close the connection after running the script by using following instead of above
expect -c 'spawn ssh $UN#$STAGE ;
expect password ; send "$PASS \n";
expect -regexp "$PROMPT"; send "./settings.$UN.sh > settings_log.txt \n";
expect -regexp "$PROMPT"; send "exit \n"'
This does close the connection but I noticed that my script file did not run at all. Also the settings_log.txt is not generated at all.
Does this mean, that exit command is aborting the process before its completion? I tried using 'sleep' before exit but it did not help. Is there a better suggested way to terminate the connection when using expect?
Any help is appreciated.
with expect, you terminate your send commands with \r not \n, so
expect -c 'spawn ssh $UN#$STAGE
expect password
send "$PASS\r"
expect -regexp "$PROMPT"
send "./settings.$UN.sh > settings_log.txt\r"
expect -regexp "$PROMPT"
send "exit\r"
expect eof'
Note you can execute remote shell commands and copy files using ssh and scp, directly, without using expect.
For example,
scp ./settings.$UN.sh $UN#$STAGE:settings_log.txt
ssh $UN#$STAGE whatever-you-need-to-execute
The connection will close as soon as soon as whatever-you-need-to-execute completes.
Your outer script seems to be written in csh and sets a variable named "prompt", but your expect script is using a variable called "PROMPT". Try making the two variable names match case.
This question already has answers here:
Using expect to pass a password to ssh
(6 answers)
Closed 5 years ago.
So I wanted to automate my SSH logins. The host I'm with doesn't allow key authentication on this server, so I had to be more inventive.
I don't know much about shell scripting, but some research showed me the command 'expect' and some scripts using it for exactly this purpose. I set up a script and ran it, it worked perfectly to login.
#!/usr/bin/env expect -f
set password "my_password"
match_max 1000
spawn ssh -p 2222 "my_username"#11.22.11.22
expect "*?assword:*"
send -- "$password\r"
send -- "\r"
expect eof
Initially, it runs as it should.
Last login: Wed May 12 21:07:52 on ttys002
esther:~ user$ expect expect-test.exp
spawn ssh -p 2222 my_username#11.22.11.22
my_username#11.22.11.22's password:
Last login: Wed May 12 15:44:43 2010 from 20.10.20.10
-jailshell-3.2$
But that's where the success ends.
Commands do not work, but hitting enter just makes a new line.
Arrow keys and other non-alphanumeric keys produce symbols like '^[[C', '^[[A', '^[OQ' etc.[1]
No other prompt appears except the two initially created by the expect script.
Any ignored commands will be executed by my local shell once expect times out.
An example:
-jailshell-3.2$ whoami
ls
pwd
hostname
(...time passes, expect times out...)
esther:~ user$ whoami
user
esther:~ ciaran$ ls
Books Documents Movies Public
Code Downloads Music Sites
Desktop Library Pictures expect-test.exp
esther:~ ciaran$ pwd
/Users/ciaran
esther:~ ciaran$ hostname
esther.local
As I said, I have no shell scripting experience, but I think it's being caused because I'm still "inside of" expect, but not "inside of" SSH. Is there any way to terminate expect once I've logged in, and have it hand over the SSH session to me?
I've tried commands like 'close' and 'exit', after " send -- "\r" ". Yeah, they do what I want and expect dies, but it vindictively takes the SSH session down with it, leaving me back where I started. What I really need is for expect to do its job and terminate, leaving the SSH session back in my hands as if I did it manually.
All help is appreciated, thanks.
[1] I know there's a name for this, but I don't know what it is. And this is one of those frightening things which can't be googled, because the punctuation characters are ignored. As a side question, what's the story here?
I think your problem has been solved here before:
Using expect to pass a password to ssh
The command you're looking for is interact. It hands the control over to you/your keyboard.
I've used a similar script to autologin.
I used "interact" and I removed "expect eof". By doing this, I can get the screen back so that I can enter commands by hand.
expect "?assword: "
send -- "$password\r"
expect "$"
interact
putting it all together, log you in and leave you on the command line exactly as though you typed it manually
#!/usr/bin/expect -f
set ip "127.001.001.001"
set password "xxyykkx"
spawn ssh $ip -l root
expect "?assword:"
send "$password\r"
interact