How do I login over ssh without using password less RSA / DSA public keys? How do I use ssh in a shell script? How do I login non-interactivly performing password authentication with SSH and shell scripts?
You can use the sshpass command to provide the password for ssh based login. It is a non-interactive ssh password auth tool. From the man page:
sshpass is a utility designed for running ssh using the mode referred to as “keyboard-interactive” password authentication, but in non-interactive mode.
ssh uses direct TTY access to make sure that the password is indeed issued by an interactive keyboard user. Sshpass runs ssh in a dedicated tty, fooling it into thinking it is getting the password from an interactive user.
The command to run is specified after sshpass’ own options. Typically it will be “ssh” with arguments, but it can just as well be any other command. The password prompt used by ssh is, however, currently hardcoded into sshpass.
Install sshpass under Debian / Ubuntu Linux
Type the following command:
$ sudo apt-get install sshpass
Install sshpass under RHEL/CentOS Linux
Install sshpass under Arch Linux
$ sudo pacman -S sshpass
Install sshpass under OpenSUSE Linux
$ sudo zypper install sshpass
Install sshpass under FreeBSD Unix
To install the port, enter:
# cd /usr/ports/security/sshpass/ && make install clean
To add the package, run:
# pkg install sshpass
How do I use sshpass in Linux or Unix?
Login to ssh server called server.example.com with password called t@uyM59bQ:
$ sshpass -p 't@uyM59bQ' ssh email@example.com
For shell script you may need to disable host key checking:
$ sshpass -p 't@uyM59bQ' ssh -o StrictHostKeyChecking=no firstname.lastname@example.org
Security unwise warning: The -p option should be considered the least secure of all of sshpass’s options. I recommend that you use ssh’s public key authentication.
A bash shell script example with SSHPASS
The syntax is:
SSHPASS='t@uyM59bQ' sshpass -e ssh email@example.com SSHPASS='t@uyM59bQ' sshpass -e ssh firstname.lastname@example.org date SSHPASS='t@uyM59bQ' sshpass -e ssh email@example.com w SSHPASS='t@uyM59bQ' sshpass -e ssh -o StrictHostKeyChecking=no firstname.lastname@example.org
SSHPASS=’t@uyM59bQ’ sshpass -e ssh email@example.com
SSHPASS=’t@uyM59bQ’ sshpass -e ssh firstname.lastname@example.org date
SSHPASS=’t@uyM59bQ’ sshpass -e ssh email@example.com w
SSHPASS=’t@uyM59bQ’ sshpass -e ssh -o StrictHostKeyChecking=no firstname.lastname@example.org
The password is passed as environment variable called SSHPASS.
Reading password from file
Another option is to read password from file using the -f option. The syntax is:
sshpass -f fileNameHere ssh user@server
Create a file as follows:
$ echo 'myPassword' > myfile $ chmod 0400 myfile $ sshpass -f myfile ssh email@example.com
$ echo ‘myPassword’ > myfile
$ chmod 0400 myfile
$ sshpass -f myfile ssh firstname.lastname@example.org
How do I backup /var/www/html using rsync?
Run rsync over SSH using password authentication, passing the password on the command line:
$ rsync --rsh="sshpass -p myPassword ssh -l username" server.example.com:/var/www/html/ /backup/
$ SSHPASS='yourPasswordHere' rsync --rsh="sshpass -e ssh -l username" server.example.com:/var/www/html/ /backup/
How do I use sshpass with gpg encrypted file?
First, create a file as follows:
$ echo 'mySshPasswordHere' > .sshpassword
Now, encrypt a file using gpg command:
$ gpg -c .sshpassword
$ rm .sshpassword
Finally, use it as follows:
$ gpg -d -q .sshpassword.gpg > fifo; sshpass -f fifo ssh email@example.com
If you just type sshpass, you will see help screen as follows:
- keychain: Set Up Secure Passwordless SSH Access For Backup Scripts
- sshpass man page
- Non-interactive ssh password auth – project home page.