Considering that they are getting different systems to talk to each other, telnet and ftp work amazingly well. Yet there are smoother interfaces available for Unix workstations, and if you interconnect them on a regular basis, these are recommended. The Unix remote commands rlogin, rsh, and rcp provide this more transparent interface by letting you treat the remote computer effectively as another file or directory on your own machine. You can then login, run commands, and copy files on the remote machine with the same ease as you do locally (which we hope is easy).
The magic that allows remote access is a file called .rhosts in the user's home directory on the remote machine. This file lists the names of accessible computers and the users who may access them. To use a remote machine, your machine and login name must be listed in the remote machine's .rhosts file. For example, now the user bohr wants to log into the machine phy1 from the machine theo. In bohr's home directory on the machine theo he creates the file .rhosts that looks like this:
theo bohr bohr will be logging in from theo. theo.copenhagen.ne bohr Same entry with full hostname.
To avoid confusion over the full hostname, theo.copenhagen.ne in this case, and the short name, theo, we include an entry for each; multiple entries cause no problems. With the .rhosts file so prepared, we can use the remote commands. If your login name is the same on both the local and remote machine, you do not need to include your login name in the .rhosts file.