I'm writing script to test unix commands. one of them is the SCP command, where the certs are set up , so it did not ask for the password on normal scenario.
scp /tmp/test.txt $userid#$hostname:$path
But assume scenario like certs were deleted or the user id is wrong then the script is not getting completed as scp asks for password
On the terminal
scp /tmp/test.txt $userid#$hostname:$path
Password:
So how can i force not to prompt for password and just fail in case it can not validate.
The scp command was stored in a variable line and is executed as below
`$line`
Typically:
scp -o BatchMode=yes ..
Taken from the scp man pages:
-B Selects batch mode (prevents asking for passwords or
passphrases).
Related
I have a shell script which I need to execute from server A which executes commands in Server B as well. But I can execute those commands only being a root user in server B.
Manually if I login to server B then I have to change the user to root and execute delete commands. To automate this I am trying to write a script and execute from server A, but it asks me for password. How do I add my password in the script? (Though it is not recommended), or please suggest if any other way to tackle this.
Add your username in /etc/sudoers with nopasswd to remove password prompt
$ visudo
user ALL=(ALL) NOPASSWD: ALL
You can use sshpass command with -p option
sshpass -p 'your_password' ssh root#your_host ls
refer manual of sshpass for more options
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)
I am using below command to open putty through windows command prompt:
PUTTY.EXE -ssh -pw "mypass" user#IP -m C:/my.sh -t
Where my.sh mentioned in above command file contains:
sudo su - rootuser
After executing the command, putty console is opened and it prompts for password.
Is there any way where I can provide this password automatically without typing it?
There's a bit of a horrible workaround using Expect and embedding a password.
This is a bad idea.
As an alternative:
Configure sudo to allow NOPASSWD.
Login directly as root using public-private key auth.
Both these introduce a degree of vulnerability, so should be used with caution - but any passwordless auth has this flaw.
Finally, after struggling for almost whole day, I got the way to get this working.
Below command can be executed from windows machine:
PLINK.EXE -t -ssh -pw "password" user#IP /home/mydir/master.sh
master.sh file is located on remote machine. And this file contains below command to execute script with sudo command without prompting password.
echo password | sudo u user -S script.sh
Here, password should be replaced with your password. user should be replaced with your actual user and script.sh is the script on remote machine that you want to fire after sudo login.
I have a shell script, which I am using to access the SMB Client:
#!/bin/bash
cd /home/username
smbclient //link/to/server$ password -W domain -U username
recurse
prompt
mput baclupfiles
exit
Right now, the script runs, accesses the server, and then asks for a manual input of the commands.
Can someone show me how to get the commands recurse, prompt, mput baclupfiles and exit commands to be run by the shell script please?
I worked out a solution to this, and sharing for future references.
#!/bin/bash
cd /home/username
smbclient //link/to/server$ password -W domain -U username << SMBCLIENTCOMMANDS
recurse
prompt
mput backupfiles
exit
SMBCLIENTCOMMANDS
This will enter the commands between the two SMBCLIENTCOMMANDS statements into the smb terminal.
smbclient accepts the -c flag for this purpose.
-c|--command command string
command string is a semicolon-separated list of commands to be executed instead of
prompting from stdin.
-N is implied by -c.
This is particularly useful in scripts and for printing stdin to the server, e.g.
-c 'print -'.
For instance, you might run
$ smbclient -N \\\\Remote\\archive -c 'put /results/test-20170504.xz test-20170504.xz'
smbclient disconnects when it is finished executing the commands.
smbclient //link/to/server$ password -W domain -U username -c "recurse;prompt;mput backupfiles"
I would comment to Calchas's answer which is the correct approach-but did not directly answer OP's question-but I am new and don't have the reputation to comment.
Note that the -c listed above is semicolon separated list of commands (as documented in other answers), thus adding recurse and prompt enables the mput to copy without prompting.
You may also consider using the -A flag to use a file (or a command that decrypts a file to pass to -A) to fully automate this script
smbclient //link/to/server$ password -A ~/.smbcred -c "recurse;prompt;mput backupfiles"
Where the file format is:
username = <username>
password = <password>
domain = <domain>
workgroup = <workgroup>
workgroup is optional, as is domain, but usually needed if not using a domain\username formatted username.
I suspect this post is WAY too late to be useful to this particular need, but maybe useful to other searchers, since this thread lead me to the more elegant answer through -c and semicolons.
I would take a different approach using autofs with smb. Then you can eliminate the smbclient/ftp like approach and refactor your shell script to use other functions like rsync to move your files around. This way your credentials aren't stored in the script itself as well. You can bury them somewhere on your fs and make it read only by root an no one else.
I need to transfer a log file to a remote host using sftp from a Linux host. I have been provided credentials for the same from my operations group. However, since I don't have control over other host, I cannot generate and share RSA keys with the other host.
So is there a way to run the sftp command (with the username/password provided) from inside the Bash script through a cron job?
I found a similar Stack Overflow question, Specify password to sftp in a Bash script, but there was no satisfactory answer to my problem.
You have a few options other than using public key authentication:
Use keychain
Use sshpass (less secured but probably that meets your requirement)
Use expect (least secured and more coding needed)
If you decide to give sshpass a chance here is a working script snippet to do so:
export SSHPASS=your-password-here
sshpass -e sftp -oBatchMode=no -b - sftp-user#remote-host << !
cd incoming
put your-log-file.log
bye
!
Another way would be to use lftp:
lftp sftp://user:password#host -e "put local-file.name; bye"
The disadvantage of this method is that other users on the computer can read the password from tools like ps and that the password can become part of your shell history.
A more secure alternative which is available since LFTP 4.5.0 is setting the LFTP_PASSWORD environment variable and executing lftp with --env-password. Here's a full example:
export LFTP_PASSWORD="just_an_example"
lftp --env-password sftp://user#host -e "put local-file.name; bye"
# Destroy password after use
export LFTP_PASSWORD=""
LFTP also includes a cool mirroring feature (can include delete after confirmed transfer --Remove-source-files):
lftp -e 'mirror -R /local/log/path/ /remote/path/' --env-password -u user sftp.foo.com
EXPECT is a great program to use.
On Ubuntu install it with:
sudo apt-get install expect
On a CentOS Machine install it with:
yum install expect
Lets say you want to make a connection to a sftp server and then upload a local file from your local machine to the remote sftp server
#!/usr/bin/expect
spawn sftp username#hostname.com
expect "password:"
send "yourpasswordhere\n"
expect "sftp>"
send "cd logdirectory\n"
expect "sftp>"
send "put /var/log/file.log\n"
expect "sftp>"
send "exit\n"
interact
This opens a sftp connection with your password to the server.
Then it goes to the directory where you want to upload your file, in this case "logdirectory"
This uploads a log file from the local directory found at /var/log/ with the files name being file.log to the "logdirectory" on the remote server
You can use lftp interactively in a shell script so the password not saved in .bash_history or similar by doing the following:
vi test_script.sh
Add the following to your file:
#!/bin/sh
HOST=<yourhostname>
USER=<someusername>
PASSWD=<yourpasswd>
cd <base directory for your put file>
lftp<<END_SCRIPT
open sftp://$HOST
user $USER $PASSWD
put local-file.name
bye
END_SCRIPT
And write/quit the vi editor after you edit the host, user, pass, and directory for your put file typing :wq .Then make your script executable chmod +x test_script.sh and execute it ./test_script.sh.
I was recently asked to switch over from ftp to sftp, in order to secure the file transmission between servers. We are using Tectia SSH package, which has an option --password to pass the password on the command line.
example : sftp --password="password" "userid"#"servername"
Batch example :
(
echo "
ascii
cd pub
lcd dir_name
put filename
close
quit
"
) | sftp --password="password" "userid"#"servername"
I thought I should share this information, since I was looking at various websites, before running the help command (sftp -h), and was i surprised to see the password option.
You can override by enabling Password less authentication. But you should install keys (pub, priv) before going for that.
Execute the following commands at local server.
Local $> ssh-keygen -t rsa
Press ENTER for all options prompted. No values need to be typed.
Local $> cd .ssh
Local $> scp .ssh/id_rsa.pub user#targetmachine:
Prompts for pwd$> ENTERPASSWORD
Connect to remote server using the following command
Local $> ssh user#targetmachine
Prompts for pwd$> ENTERPASSWORD
Execute the following commands at remote server
Remote $> mkdir .ssh
Remote $> chmod 700 .ssh
Remote $> cat id_rsa.pub >> .ssh/authorized_keys
Remote $> chmod 600 .ssh/authorized_keys
Remote $> exit
Execute the following command at local server to test password-less authentication.
It should be connected without password.
$> ssh user#targetmachine
The easiest way I found to accomplish this, without installing any third-party library like Expect, SSHPASS...etc, is by using a combination of CURL, and SFTP. Those two are almost in every Linux machine.
This is the command you should execute, after changing the values.
curl -k "sftp://SERVER_IP:SERVER_PORT/FULL_PATH_OF_THE_FILE" --user "SERVER_USER:SERVER_PASSOWRD" -o "THE_NAME_OF_THE_FILE_AFTER_DOWNLOADING_IT"
Example:
curl -k "sftp://10.10.10.10:77/home/admin/test.txt" --user "admin:123456" -o "test.txt"
Explanation:
We are connecting to the server 10.10.10.10:77 using the username admin and password 123456, to move the file /home/admin/test.txt from that server to the server you are using currently to execute the above command.
Combine sshpass with a locked-down credentials file and, in practice, it's as secure as anything - if you've got root on the box to read the credentials file, all bets are off anyway.
Bash program to wait for sftp to ask for a password then send it along:
#!/bin/bash
expect -c "
spawn sftp username#your_host
expect \"Password\"
send \"your_password_here\r\"
interact "
You may need to install expect, change the wording of 'Password' to lowercase 'p' to match what your prompt receives. The problems here is that it exposes your password in plain text in the file as well as in the command history. Which nearly defeats the purpose of having a password in the first place.
You can use sshpass for it. Below are the steps
Install sshpass For Ubuntu - sudo apt-get install sshpass
Add the Remote IP to your known-host file if it is first time
For Ubuntu -> ssh user#IP -> enter 'yes'
give a combined command of scp and sshpass for it.
Below is a sample code for war coping to remote tomcat
sshpass -p '#Password_For_remote_machine' scp /home/ubuntu/latest_build/abc.war #user##RemoteIP:/var/lib/tomcat7/webapps
You can use a Python script with scp and os library to make a system call.
ssh-keygen -t rsa -b 2048 (local machine)
ssh-copy-id user#remote_server_address
create a Python script like:
import os
cmd = 'scp user#remote_server_address:remote_file_path local_file_path'
os.system(cmd)
create a rule in crontab to automate your script
done
A few people have mentioned sshpass but not many clear coding examples...
This is how we are doing it with bash scripts for rsync backups:
sshpass -p "${RSYNC_PASSWORD}" sftp "${RSYNC_USER}"#"${RSYNC_REMOTE_HOST}"
Keep in mind you will have to sudo apt install sshpass before this works properly.