[[General meaning in software]] [[much used in Tcl]] In Tcl, to ''enhance'' a core command (or existing proc) by renaming the command to be enhanced, then creating a procedure with the same name as the core command that provides the desired functionality. Easy example, provided by [RS]: rename exit _exit proc exit {{code 0}} { set fp [open test a] puts $fp "trapped exit at [clock format [clock seconds]]" _exit $code } [[General case needs [uplevel] ...]] ---- [Category Development]