Check out Alpha 2.5.58
If you use TCP ports on Linux along with the system port (for catching events like CTRL-C and other terminators) or the CALL function (for launching external programs), you will want to try out this new release. A long standing bug has been fixed that caused interference between these types of events. It's important for you to help us verify that these problems are fixed. These releases are found on their usual page.
In addition, you will notice a different Linux shell response when you press CTRL-C. You should see "REBOL terminated" on the error output file (so you will always see it). This is an indication that REBOL got the termination request and acted on it. Before you had to guess. Now you know.
Also, the termination process is different in that REBOL attempts to close all open ports. Note that if this fails and causes a recursion into the termination code, REBOL will immediately abort to avoid a loop.
One more change: when running CALL the security dialog will now inform users that a "Script requests permission to execute a system shell command" followed by the command string. This is much more clear than the prior message.