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5.22. Running a Single Command with xterm -e

The -e option to xterm is useful for running a single command before exiting. For example, if you just want to run a character-based mail program, type the following:

% xterm -e mail

When you quit the mail program, the xterm window exits.

The -e option needs to be the last xterm option on the command line. The remainder of the command line is assumed to be part of the command to be executed by xterm. The new window has the command name in its titlebar by default (unless overridden by other command-line options (Section 5.15)).

One use for xterm -e is for running a window with a login session to a remote system, like this:

% xterm -e ssh hostname &

Figure Go to http://examples.oreilly.com/upt3 for more information on: ssh-agent

The xterm process runs on the local system, but immediately logs you into the remote machine. You are prompted for a password in the new xterm that pops up -- before you can log in to the remote system. This isn't as convenient as putting that command in your X setup file (like .xinitrc or .xsession) -- but it's far more secure because you don't need to put your hostname in your .rhosts or .shosts file (Section 1.21), which is a potential security hole. (Or, if you use ssh for your remote login -- and you start ssh-agent before you start X -- you won't need to type passwords at all during your X session. This is the handiest setup by far.)

You can use -e to create a makeshift X display for any character-based programs you like to run. For example, you might want to keep track of messages sent to the console, but you can't run xterm -C to get console messages because you aren't actually logged in on the console. You might run something like this:

tail -f Section 12.10

% xterm -e tail -f /var/log/messages &

Section 24.21 has more about how this works.

--LM, JP, and SJC

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