This is the fourth in a series of posts describing new features in the upcoming 8.7 release of Tcl. It introduces the new process command added to allow monitoring and management of subprocesses spawned from Tcl.

One of the strengths of Tcl is the ease of integration with other software, whether they be COM components, libraries or even executable programs that are not designed for interaction with other programs. Here we look the facilities Tcl offers related to the last of these -- running external programs and optionally interacting with them using standard I/O mechanisms.