I am currently trying to create a script with error handling.
Basically the script tests the ssh connection with this command :
ssh -o BatchMode=yes $machine uname -a
There is 3 potential situation that i want to handle :
SSH works just fine without password
SSH is blocked because the machine isn't in the known_hosts file in .ssh
SSH is blocked because the machine isn't in the known_hosts file in .ssh AND it requires a password to continue (which means the id_rsa.pub isn't in the authorized_keys file in .ssh
I have on main script that is calling an expect script here is what the main script looks like :
ssh -o BatchMode=yes ${machine} uname -a &> temp-file.txt 2>&1
# Here we test the ssh connection just once and we store the output of the command in a temp file
if [ $? -eq 255 ]
# If the ssh didn't work
then
if grep -q "Host key verification failed." temp-file.txt
# If the error message is "Host key verification failed."
then
expect script-expect-knownhosts.exp ${machine} 2>&1 >/dev/null
And here is the script-expect-knownhosts.exp file in which i tried to make a condition :
#!/usr/bin/expect -f
set machine [lindex $argv 0]
# Here we state that the first argument used with the command will be the $machine variable
set prompt "#|%|>|\$ $"
set timeout 60
spawn ssh $machine
# We do a ssh on the machine
set prompt "#|%|>|\$ $"
expect {
"Are you sure you want to continue connecting (yes/no)? " {send "yes\r";exp_continue}
# If he asks for a yes/no answer, then answer yes to add the machine to the known_hosts file
-exact "Password: " {send -- "^C";exp_continue}
# If he asks for a password, then send a CTRL + C
-re $prompt {send "exit\r";exp_continue}
# If the prompt shows up (if after the yes/no question, we don't need to put a password in) then type exit
}
So here is what happens when i execute the expect script with a machine in case number 2 (works just fine):
spawn ssh machine
Are you sure you want to continue connecting (yes/no)? yes
machine:~ # exit
deconnection
Connection to machine closed.
And here is what happens when i execute the expect script with a machine in case number 3 :
spawn ssh machine
Are you sure you want to continue connecting (yes/no)? yes
Password:
And it stays stuck on Password until i manually do a CTRL + C
In cases 2 and 3 you don't need exp_continue because you are stopping the connection process.
For case 2, I don't think you really want to send a control-C. When you do this interactively, typing control-C has the effect of sending a signal to kill the process you are interacting with. What you really want is to stop the ssh process, so instead of send -- "^C";exp_continue you should just do close.
I'm trying to use expect in a Bash script to provide the SSH password. Providing the password works, but I don't end up in the SSH session as I should. It goes back strait to Bash.
My script:
#!/bin/bash
read -s PWD
/usr/bin/expect <<EOD
spawn ssh -oStrictHostKeyChecking=no -oCheckHostIP=no usr#$myhost.example.com'
expect "password"
send "$PWD\n"
EOD
echo "you're out"
The output of my script:
spawn ssh -oStrictHostKeyChecking=no -oCheckHostIP=no usr#$myhost.example.com
usr#$myhost.example.com's password: you're out
I would like to have my SSH session and, only when I exit it, to go back to my Bash script.
The reason why I am using Bash before expect is because I have to use a menu. I can choose which unit/device to connect to.
To those who want to reply that I should use SSH keys, please abstain.
Mixing Bash and Expect is not a good way to achieve the desired effect. I'd try to use only Expect:
#!/usr/bin/expect
eval spawn ssh -oStrictHostKeyChecking=no -oCheckHostIP=no usr#$myhost.example.com
# Use the correct prompt
set prompt ":|#|\\\$"
interact -o -nobuffer -re $prompt return
send "my_password\r"
interact -o -nobuffer -re $prompt return
send "my_command1\r"
interact -o -nobuffer -re $prompt return
send "my_command2\r"
interact
Sample solution for bash could be:
#!/bin/bash
/usr/bin/expect -c 'expect "\n" { eval spawn ssh -oStrictHostKeyChecking=no -oCheckHostIP=no usr#$myhost.example.com; interact }'
This will wait for Enter and then return to (for a moment) the interactive session.
The easiest way is to use sshpass. This is available in Ubuntu/Debian repositories and you don't have to deal with integrating expect with Bash.
An example:
sshpass -p<password> ssh <arguments>
sshpass -ptest1324 ssh user#192.168.1.200 ls -l /tmp
The above command can be easily integrated with a Bash script.
Note: Please read the Security Considerations section in man sshpass for a full understanding of the security implications.
Add the 'interact' Expect command just before your EOD:
#!/bin/bash
read -s PWD
/usr/bin/expect <<EOD
spawn ssh -oStrictHostKeyChecking=no -oCheckHostIP=no usr#$myhost.example.com
expect "password"
send -- "$PWD\r"
interact
EOD
echo "you're out"
This should let you interact with the remote machine until you log out. Then you'll be back in Bash.
After looking for an answer for the question for months, I finally find a really best solution: writing a simple script.
#!/usr/bin/expect
set timeout 20
set cmd [lrange $argv 1 end]
set password [lindex $argv 0]
eval spawn $cmd
expect "assword:" # matches both 'Password' and 'password'
send -- "$password\r"; # -- for passwords starting with -, see https://stackoverflow.com/a/21280372/4575793
interact
Put it to /usr/bin/exp, then you can use:
exp <password> ssh <anything>
exp <password> scp <anysrc> <anydst>
Done!
A simple Expect script:
File Remotelogin.exp
#!/usr/bin/expect
set user [lindex $argv 1]
set ip [lindex $argv 0]
set password [lindex $argv 2]
spawn ssh $user#$ip
expect "password"
send "$password\r"
interact
Example:
./Remotelogin.exp <ip> <user name> <password>
Also make sure to use
send -- "$PWD\r"
instead, as passwords starting with a dash (-) will fail otherwise.
The above won't interpret a string starting with a dash as an option to the send command.
Use the helper tool fd0ssh (from hxtools, source for ubuntu, source for openSUSE, not pmt). It works without having to expect a particular prompt from the ssh program.
It is also "much safer than passing the password on the command line as sshpass does" ( - comment by Charles Duffy).
Another way that I found useful to use a small Expect script from a Bash script is as follows.
...
Bash script start
Bash commands
...
expect - <<EOF
spawn your-command-here
expect "some-pattern"
send "some-command"
...
...
EOF
...
More Bash commands
...
This works because ...If the string "-" is supplied as a filename, standard input is read instead...
sshpass is broken if you try to use it inside a Sublime Text build target, inside a Makefile. Instead of sshpass, you can use passh
With sshpass you would do:
sshpass -p pa$$word ssh user#host
With passh you would do:
passh -p pa$$word ssh user#host
Note: Do not forget to use -o StrictHostKeyChecking=no. Otherwise, the connection will hang on the first time you use it. For example:
passh -p pa$$word ssh -o StrictHostKeyChecking=no user#host
References:
Send command for password doesn't work using Expect script in SSH connection
How can I disable strict host key checking in ssh?
How to disable SSH host key checking
scp without known_hosts check
pam_mount and sshfs with password authentication
I need to create a bash script that will remotely run another script on a batch of machines. To do so I am passing a script through SSH.
ssh -p$port root#$ip 'bash -s' < /path/to/script/test.sh
I thought it would use my RSA keys but I am getting error:
"Enter password: ERROR 1045 (28000): Access denied for user 'root'#'localhost' (using password: YES)"
I tried using sshpass to no avail. So my next solution was using expect. I have never used expect before and I'm positive my syntax is way off.
ssh -p$port root#$ip 'bash -s' < /path/to/script/test.sh
/usr/bin/expect <<EOD
expect "password"
send "$spass\n"
send "\n"
EOD
I have root access to all machines and ANY solution will do as long as the code remains within bash. Just keep in mind that this will be done in a loop with global variables ($spass, $ip, $port, etc) passed from a parent script.
You are doing it wrong in two means:
If you want expect to interact with ssh, you need to start ssh from expect script and not before.
If you put the script (/path/to/script/test.sh) to stdin of ssh, you can't communicate with the ssh process any more.
You should rather copy the script to remote host using scp and then run it.
Expect script might look like this:
/usr/bin/expect <<EOF
spawn ssh -p$port root#$ip
expect "password"
send "$Spass\r"
expect "$ "
send "/path/to/script/on/remote/server/test.sh\r"
expect "$ "
interact
EOF
#!/usr/bin/expect
#Replace with remote username and remote ipaddress
spawn /usr/bin/ssh -o StrictHostKeyChecking=no username#IPAddress
#Replace with remote username and remote ipaddress
expect "username#IPAddress's password: "
#Provide remote system password
send "urpassword\n"
#add commands to be executed. Also possible to execute bash scripts
expect "$ " {send "pwd\n"} # bash command
expect "$ " {send "cd mytest\n"}
expect "$ " {send "./first.sh\n"} # bash scripts
expect "$ " {send "exit\n"}
interact
I am trying to execute expect command inside by small bash script to login into servers using key authentication method. My script is as follows:
#!/bin/bash
HOST=$1
/usr/bin/expect -c "
spawn ssh -i /root/.ssh/id_rsa root#$HOST
expect -exact "Enter passphrase for key '/root/.ssh/id_rsa': " ;
send "PASSPHRASE\n" ;
interact
"
Output with error is:
spawn ssh -i /root/.ssh/id_rsa root#server.domain.com
couldn't read file "passphrase": no such file or directory
Can you help to correct this?
There is a quoting issue in your code. Rather than trying to pass commands to expect on the command line save your code as an Expect script. You can then run it from a shell script or otherwise.
script.exp
#!/usr/bin/expect
# usage: ./script.exp host
set HOST [lindex $argv 0]
spawn ssh -i /root/.ssh/id_rsa root#$HOST
expect -exact "Enter passphrase for key '/root/.ssh/id_rsa': "
send "PASSPHRASE\n"
interact
However, if that's all you're doing with Expect in this case I second the suggestion to use ssh-agent instead.
I am new to Linux Shell Scripting.I need to execute a shell script that gets username, password, host-name, command-to-be-executed as 1,2,3,4 parameters respectively. I used expect command but it prompts for password again.The main theme of this script is to execute a command from a remote server. Password security issues is not a problem. The main issue is that I must not be prompted for password input. I have to run this for about 80 servers, so I cant provide password for each and every time. Please help me solving this.
My script:
echo username = $1
echo Password = $2
echo Host-Name = $3
echo Command to Be executed = $4
expect -c "spawn ssh -oStrictHostKeyChecking=no -oCheckHostIP=no $1#$3 $4; expect \"*assword:*\"; send "$2"; interact
#expect eof
"
My Output:
username = root
Password = root#123
Host-Name = host-name
Command to Be executed = ls
spawn ssh -oStrictHostKeyChecking=no -oCheckHostIP=no root#host-name ls
root#host-name's password:
~
first your index will start at 0 not 1 so username = $0
also you need to set your variables like so: (this is the expect script i use on sever hundred nodes)
#!/usr/bin/expect
set user [lindex $argv 0]
set password [lindex $argv 2]
set ip [lindex $argv 2]
set command [lindex $argv 3]
spawn ssh -o StrictHostKeyChecking=no "$user\#$ip"
expect "assword:"
send "$password\r";
expect "$ "
send "$command\r"
expect "$ "
send "exit\r"