I‘m a new Ubutnu Linux user. I backup files to our corporate Unix backup server using the rsync command. The server only allow to upload/download files.
I am unable to login to the server. How do change my password using the passwd command over ssh based session?
For security reasons, your ssh based account has limited access to the server. You can only upload or download files using scp, sftp, rsync and so on. You may execute limited number of commands such as passwd, ls and so on.
Also, it is a good idea to change your password every month or at least every four months. Make sure you use combination of alphabets (upper and lower case characters), numbers, and special characters as a password to safeguard your account. You should choose a password of at least ten characters.
The syntax is:
-t : This option force pseudo-tty allocation. This can be used to execute arbitrary screen-based programs (such as passwd) on a remote machine, which can be very useful, e.g. when implementing menu services. Multiple -t options force tty allocation, even if ssh has no local tty.
In this example, change password for user called nixcraft on server1.cyberciti.biz by issuing the passwd command over ssh:
ssh -t firstname.lastname@example.org passwd
ssh -t vivek@nas01 passwd
Animated gif 01: Change password using the passwd command over ssh
Warning: If you skip the -t option, either you will see password in a plain text on screen or you will get an error that read as follows:
passwd: pam_chauthtok(): conversation failure
In this example, change password for user called vivek on nas01 by issuing the passwd command without the -t over ssh:
ssh email@example.com passwd
ssh vivek@nas01 passwd
Animated gif 02: Change password using the passwd command without -t option over ssh. Note the password is shown in clear text.
Read man pages for more info: ssh(1),passwd(1)