Both the client and the server must have ssh service (daemon) running. They are normally available on newer Linux distributions (e.g., RH7.0). Before using ssh, some setup may be necessary. The user creates his/her RSA key pair (for encryption) by running the command ssh-keygen. This stores the private key in the file $HOME/.ssh/identity and the public key in $HOME/.ssh/identity.pub in the user's home directory. To allow automatic login, the user should copy the identity.pub to $HOME/.ssh/authorized_keys in his/her home directory on the remote machine After this, the user can log in without giving the password. The most convenient way to use RSA authentication may be with an authentication agent. See man 1 ssh-agent for more information. If automatic authentication methods fail, ssh prompts the user for a password. The password is sent to the remote host for checking; however, since all communications are encrypted, the password cannot be seen by someone listening on the network.
From: Benjamin Smith <bens@benjamindsmith.com> (edited for space):
I recently got openssh 2.9.2p1 up and running, along with the password-free login option. It took some doing and none of the howtos covered this. Would you like the "magic tidbit" that makes it all work? Here it is: "the default is to SSH2 and DSA keys, which you generate with 'ssh-keygen -d' and it goes into ~/.ssh/id_dsa.pub, which you would copy to remotehost:.ssh/authorized_keys2" Use this instead of the usual "authorized_keys" file given in the howtos, and VOILA! It actually works.
ftp server
Ftp another machine. (There is also ncftp which adds extra features and gftp for GUI .) Ftp is good for copying files to/from a remote machine. Try user "anonymous" if you don't have an account on the remote server. After connection, use "?" to see the list of available ftp commands. The essential ftp commands are: ls (see the files on the remote system), ASCII,binary (set the file transfer mode to either text or binary, important that you select the proper one ), get (copy a file from the remote system to the local system), mget (get many files at once), put (copy a file from the local system to the remote system), mput (put many files at once), bye (disconnect). For automation in a script, you may want to use ncftpput and ncftpget, for example:
ncftpput -u my_user_name -p my_password -a remote.host.domain remote_dir *local.html
"ncftp" seems to have a problem if your computer is behind a firewall--you need to configure the file /home/usr_name/.ncftp/firewall. Alternatively, you may use "lftp" to accomplish the same, for example:
lftp -e "mput -a *local.html" -u my_user_name,my_password ftp://remote.host.domain
For keeping mirrors of ftp directories, one can use fmirror
wget -m --no-parent http://sunsite.dk/linux-newbie
Copy files from web sites. The example above uses the option -m (=mirror) to retrieve a complete set of files from the master site of this guide. The option "--no-parent" limits the retrieval to the files in the given directory and its subdirectories.
minicom
Minicom program for serial port "terminal emulation". Looks and works like "Procomm" or "Telix". It is useful for testing and debugging your serial communication.
rx
Receive files using the Zmodem, Ymodem, or Xmodem protocol. Xmodem requires a filename. Use rx --help for more info. Who uses these protocols any more anyway?
"I use Zmodem regularly. I have two computers running (SuSE) Linux, a laptop and a desktop. The desktop computer does not have access to an internet connection. So, in order to get files I downloaded from one computer to the other, I send them over via a null-modem cable, using Minicom and the Zmodem protocol. This way I can even connect my laptop from work running Win2000 to my Linux machine using Reflexion (a win32 terminal emulation prog)" (from Berry Vos, B.Vos@getronics.com, 2001 08 28).
