SSH clients
SSH (secure shell) client enables us to transfer command and data via secured protocol.
Windows
putty is the most famous SSH client for Windows. The putty is a console application that emulates xterm. If you want to transfer files, you can use WinSCP. The WinSCP is easy to use because it has a graphical interface.
<float leftbox300>
Putty
- putty - Official
</float>
<float leftbox300>
WinSCP
</float> <clear/>
Macintosh
As you know, you can use 'ssh' and 'sftp' in Terminal application. 
<float leftbox300>
SSH login
#ssh name@somewhere.co.jp
</float>
<float leftbox300>
SFTP login
#sftp name@ftpserver.co.jp
</float> <clear/>