The default implementation of Tcl supports a C-shell like command recall mechanism. The history command gives a numbered list of the most recently entered commands. Any command in the list can be re-executed by entering !n, where n is the number of the command in the history list. The previous command can be re-executed by entering !!. The most recent command that begins with a string can be re-executed by entering !prefix, where prefix is the string with which the command begins.
Note that command recall is implemented using the Tcl unknown procedure, which is a script file loaded by Tcl at run time and may be different or not exist on your system. See the section below on the unknown command for more details on how it is implemented in XSPEC.