An ASCII text file (with the extension .tcl) that uses Tcl script, which is a scripting language for controlling and extending applications. A Tcl Script File contains a single Tcl script, which is composed of Tcl commands and Quartus II Application Programming Interface (API) functions used as commands. You can use the Quartus II Text Editor to create and edit Tcl Script Files.
You can run Tcl scripts in command-line mode to control and extend the Quartus II software. You can also run Tcl scripts in the Quartus II Tcl Console window or using the Tcl Scripts command on the Tools menu.