rsh (remote shell) is a command line computer program which can execute shell commands as another user, and on another computer across a computer network. The remote system on which the rsh executes the command needs to be running the rshd daemon.

rsh originated as part of the unix operating system, along with rcp as part of the rlogin package on Berkeley Software Distribution version 4.2 in 1983. rsh has since been ported to other operating systems.

As described in the rlogin article, the rsh protocol is not secure for network use, because it sends unencrypted information over the network, among other things. Some implementations also authenticate by sending unencrypted passwords over the network. rsh has largely been replaced by the very similar ssh (secure shell) program on untrusted networks like the internet.

As an example of rsh use, the following executes the command mkdir testdir as remoteuser on the computer remoteconputer

 rsh -l remoteuser remotecomputer "mkdir testdir" 

After the command has finished rsh terminates. If no command is specified then rsh will log in on the remote system using rlogin.

References

• rsh - remote shell (http://unixhelp.ed.ac.uk/CGI/man-cgi?rsh) - rsh man page.