I'm trying to test ssh trust between a linux box against 12 other linux boxes using a shell script and I'm trying to pass user input as 'yes' for the question below automatically.
Are you sure you want to continue connecting (yes/no)?
but the script is failing with error 'Host key verification failed'. I manually executed the ssh command with << EOT on one of the server but the I still get user prompt question. Is there any-other way to pass input value for user prompts automatically while running ssh command?
Note: I cannot use spawn or except do you some system limitation and I cannot install them due to organisations access restrictions.
I tried with the following options but none of them worked for me
[command] << [EOT, EOL, EOF]
echo 'yes'
[EOT, EOL, EOF]
yes | ./script.sh
printf "yes" | ./script.sh
echo "yes" | ./script.sh
./script.sh 'read -p "Are you sure you want to continue connecting (yes/no)?";echo "yes"'
sh```
for server in `cat server_list` ; do
UPPER_MACHINE_NAME=`echo $server | cut -d '.' -f 1`
UPPER_MACHINE_NAME=${UPPER_MACHINE_NAME^^}
ssh -tt user#$UPPER_MACHINE_NAME << EOT
echo 'yes'
touch /usr/Finastra/sshtest.txt
EOT
done
```
Related
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 am making a script to securely transfer data between my two machines through scp.
But in the script, it shows an error due to no password. So how can I make my shell script to ask me for password after executing scp command?
Here is my csh script.
# ssh shahk#sj-shahk
# ls -al
echo "Source Location of Remote Server - $1"
echo "Destination Location of Local Server - $2"
echo "File/Folder to be Transferred from Remote Server - $3"
echo "File Transfer Starts"
scp -rv $1/$3 <username>#<hostname>:$2
echo "File Transfer Completed"
# exit
Now I am using the above script with ssh in following way.
ssh <username>#<hostname> "<script name> <args>"
When I use in the above manner, it does not prompt for password while executing scp command.
You can use sshpass
https://www.cyberciti.biz/faq/noninteractive-shell-script-ssh-password-provider/
I have used it once to directly scp or ssh without prompting password.
For example :
sshpass -p 'password' scp file.tar.gz root#xxx.xxx.xxx.194:/backup
As mentioned by the other answer, sshpass will do the job perfectly. In the case where you can not install new packages on your local computer, you can also use expect (installed by default on most distros) to automate your interactive session.
The basic syntax of expect is to wait for the program to display a specific string (expect mystring), which triggers a specific behaviour (send command)
The following script shows the basic structure to implement what you need :
#!/usr/bin/expect -f
# syntax to specify which command to monitor
spawn scp myfile user#remote.host:/dest_folder
# this syntax means we expect the spawned program to display "password: "
# expect can understand regex and glob as well. read the man page for more details
expect "password: "
# the \r is needed to submit the command
send "PASSWORD\r"
# expect "$ " means we wait for anything to be written.
# change if you want to handle incorrect passwords
expect "$ "
send "other_command_to_execute_on_remote\r"
expect "$ "
send "exit\r"
As a side note, you can also set up passwordless authorizations through ssh keys.
#1) create a new ssh key on your local computer
> ssh-keygen -t rsa
#2) copy your public key to your remote server
# you will need to login, but only once. Once the key is on the remote server, you'll be able to connect without password.
> ssh-copy-id -i ~/.ssh/id_rsa.pub user#ip_machine
# OR
> cat ~/.ssh/id_rsa.pub | ssh user#ip_machine "cat - >> ~/.ssh/authorized_keys"
This tutorial explains how to use the keychain tool to manage several ssh keys and users.
ssh <username>#<hostname> "<script name> <args>"
scp will only read a password from a TTY, and it doesn't have a TTY in this case. When you run ssh and specify a command to be executed on the remote system (as you're doing here), ssh by default doesn't allocate a PTY (pseudo-tty) on the remote system. Your script and all of the commands launched from it--including scp--end up running without a TTY.
You can use the ssh -t option to make it allocate a tty on the remote system:
ssh -t <username>#<hostname> "<script name> <args>"
If you get a message like "Pseudo-terminal will not be allocated because stdin is not a terminal", then add another -t:
ssh -tt <username>#<hostname> "<script name> <args>"
So here is my problem, I have this script I wrote where I'm exporting two variables however they're not making it into the subshell.
The point of this script is to change a users password and clear out their pam_tally for CentOS and Ubuntu hosts.
A little background is that this environment's users are managed by puppet but the passwords are all local, ssh keys are not allowed either (this is set in stone and can't be changed so I have to work with what I got) and the reason is that every log in has to be manual (even number of sessions are limited to two so you can't even user csshX effectively).
Here is my script
#!/bin/bash
echo "Please enter user whose password you want to change"
read NEWUSER
echo "Please enter new password for user"
read -s -p "Temp Password:" TEMPPASSWORD
PASSWORD=$TEMPPASSWORD
export PASSWORD
NEWUSER2=$NEWUSER
export NEWUSER2
for i in HOST{cluster1,cluster2,cluster3}0{1..9}
do
ping -c 2 $i && (echo $i ; ssh -t $i '
sudo pam_tally2 --user=$NEWUSER2 --reset
echo -e "$PASSWORD\n$PASSWORD" | sudo passwd $NEWUSER2
sudo chage -d 0 $NEWUSER2
')
done
You are using ssh to connect to a remote host and run a script on that host. ssh does not export the local environment to the remote session but instead performs a login on the remote host which sets the environment according to the remote user's configuration on the remote host.
I suggest you pass all needed values via the command you want to execute. This could be done like this:
ssh -t $i '
sudo pam_tally2 --user='"$NEWUSER2"' --reset
echo -e "'"$PASSWORD"'\n'"$PASSWORD"'" | sudo passwd '"$NEWUSER2"'
sudo chage -d 0 '"$NEWUSER2"
Watch closely how this uses quotes. At each occasion where you used a variable, I terminate the single-quoted string (using '), then add a double-quoted use of the variable (e. g. "$PASSWORD") and then start the single-quoted string again (using ' again). This way, the shell executing the ssh command will expand the variables already, so you have no need to pass them into the remote shell.
But be aware that special characters in the password (like " or ' or or maybe a bunch of other characters) can mean trouble using this simple mechanism. To be safe against this as well, you would need to use the %q format specifier of the printf command to quote your values before passing them:
ssh -t "$i" "$(printf '
sudo pam_tally2 --user=%q --reset
{ echo %q; echo %q; } | sudo passwd %q
sudo chage -d 0 %q' \
"$NEWUSER2" "$PASSWORD" "$PASSWORD" "$NEWUSER2" "$NEWUSER2")"
I need to collect user information from 100 remote servers. We have public/private key infrastructure for authentication, and I have configured ssh-agent command to forward key, meaning i can login on any server without password prompt (auto login).
Now I want to run a script on all server to collect user information (how many user account we have on all servers).
This is my script to collect user info.
#!/bin/bash
_l="/etc/login.defs"
_p="/etc/passwd"
## get mini UID limit ##
l=$(grep "^UID_MIN" $_l)
## get max UID limit ##
l1=$(grep "^UID_MAX" $_l)
awk -F':' -v "min=${l##UID_MIN}" -v "max=${l1##UID_MAX}" '{ if ( $3 >= min && $3 <= max && $7 != "/sbin/nologin" ) print $0 }' "$_p"
I don't know how to run this script using ssh without interaction??
Since you need to log into the remote machine there is AFAICT no way to do this "without ssh". However, ssh accepts a command to execute on the remote machine once logged in (instead of the shell it would start). So if you can save your script on the remote machine, e.g. as ~/script.sh, you can execute it without starting an interactive shell with
$ ssh remote_machine ~/script.sh
Once the script terminates the connection will automatically be closed (if you didn't configure that away purposely).
Sounds like something you can do using expect.
http://linux.die.net/man/1/expect
Expect is a program that "talks" to other interactive programs according to a script. Following the script, Expect knows what can be expected from a program and what the correct response should be.
If you've got a key on each machine and can ssh remotehost from your monitoring host, you've got all that's required to collect the information you've asked for.
#!/bin/bash
servers=(wopr gerty mother)
fmt="%s\t%s\t%s\n"
printf "$fmt" "Host" "UIDs" "Highest"
printf "$fmt" "----" "----" "-------"
count='awk "END {print NR}" /etc/passwd' # avoids whitespace problems from `wc`
highest="awk -F: '\$3>n&&\$3<60000{n=\$3} END{print n}' /etc/passwd"
for server in ${servers[#]}; do
printf "$fmt" "$server" "$(ssh "$server" "$count")" "$(ssh "$server" "$highest")"
done
Results for me:
$ ./doit.sh
Host UIDs Highest
---- ---- -------
wopr 40 2020
gerty 37 9001
mother 32 534
Note that this makes TWO ssh connections to each server to collect each datum. If you'd like to do this a little more efficiently, you can bundle the information into a single, slightly more complex collection script:
#!/usr/local/bin/bash
servers=(wopr gerty mother)
fmt="%s\t%s\t%s\n"
printf "$fmt" "Host" "UIDs" "Highest"
printf "$fmt" "----" "----" "-------"
gather="awk -F: '\$3>n&&\$3<60000{n=\$3} END{print NR,n}' /etc/passwd"
for server in ${servers[#]}; do
read count highest < <(ssh "$server" "$gather")
printf "$fmt" "$server" "$count" "$highest"
done
(Identical results.)
ssh remoteserver.example /bin/bash < localscript.bash
(Note: the "proper" way to authenticate without manually entering in password is to use SSH keys. Storing password in plaintext even in your local scripts is a potential security vulnerability)
You can run expect as part of your bash script. Here's a quick example that you can hack into your existing script:
login=user
IP=127.0.0.1
password='your_password'
expect_sh=$(expect -c "
spawn ssh $login#$IP
expect \"password:\"
send \"$password\r\"
expect \"#\"
send \"./$remote_side_script\r\"
expect \"#\"
send \"cd /lib\r\"
expect \"#\"
send \"cat file_name\r\"
expect \"#\"
send \"exit\r\"
")
echo "$expect_sh"
You can also use pscp to copy files back and forth as part of a script so you don't need to manually supply the password as part of the interaction:
Install putty-tools:
$ sudo apt-get install putty-tools
Using pscp in your script:
pscp -scp -pw $password file_to_copy $login#$IP:$dest_dir
maybe you'd like to try the expect command as following
#!/usr/bin/expect
set timeout 30
spawn ssh -p ssh_port -l ssh_username ssh_server_host
expect "password:"
send "your_passwd\r"
interact
the expect command will catch the "password:" and then auto fill the passwd your send by above.
Remember that replace the ssh_port, ssh_username, ssh_server_host and your_passwd with your own configure
Lets assume the script i want to write ssh to 1.2.3.4 and then invokes
ls.
The problem is that when the line "ssh 1.2.3.4" is invoked, a password is
Required, hence, the flow is stopped, even when i fill the password,
The script wont continue.
How can i make the script continue after the password is given?
Thx!
You want to do public key authentication. Here are some resources which should get you going.
http://magicmonster.com/kb/net/ssh/auto_login.html
http://www.cs.rpi.edu/research/groups/vision/doc/auto/ssh/ssh_public_key_authentication.html
I would post a couple more links, but I don't have enough reputation points. ;) Just google on "SSH automated login" or "SSH public key authentication" if you need more help.
Actually you're trying to run ls locally but you have an ssh session opened. So it won't run ls until the session is opened. If you want to run ls remotely, you should use
ssh username#host COMMAND
Where command is the command you want to run. Ssh session will finish as soon as the command is invoked and you can capture its output normally.
I would suggest you to use RSA authentication method for script that needs ssh.
I just tried this script:
#!/bin/sh
ssh vps1 ls
mkdir temp
cd temp
echo test > file.txt
And it works. I can connect to my server and list my home. Then, locally, it creates temp dir, cd into it and then creates file.txt with 'test' inside.
write simple login bash script named login_to and give exec permissions (chmod 744 login_to)
#!/bin/bash
if [ $1 = 'srv1' ]; then
echo 'srv1-pass' | pbcopy
ssh root#11.11.11.11
fi
if [ $1 = 'foo' ]; then
echo 'barbaz' | pbcopy
ssh -t dux#22.22.22.22 'cd ~/somedir/someotherdir; bash'
fi
now use it like this
login_to srv1
login_to foo
When asked for password, just pate (ctrl+v or command+v) and you will be logged in.