12. A network management system employing at least one hardware processor comprising: a network manager including the at least one hardware processor; a storage device in which the network manager stores a set of design filters; a graphical user interface through which users interact with the network manager; and a network interface through which the network manager obtains information about network devices; the network manager configured to store the set of design filters in the storage device by providing at least one input screen via the graphical user interface; receiving a design filter script via the at least one input screen, wherein the design filter script includes primitives for searching lines and paragraphs in the network device configuration files having specified attributes; converting the design filter script into an executable design filter, the executable design filter configured to implement the searching when executed; and storing at least one of the design filter script or the executable design filter in the storage device; the network manager further configured to receive, via the graphical user interface, user input identifying a selected design filter from among the set of design filters and selecting a plurality of network device configuration files; the network manager further configured to apply the selected design filter to the plurality of selected network device configuration files to produce filtered results, including the filtered results for the plurality of network device configuration files; and the network manager further configured to provide the filtered results via the graphical user interface for display on a user display device, the filtered results provided via a screen having at least two windows arranged side-by-side within the screen, each window including the filtered results associated with one of the plurality of network device configuration files, the filtered results displayed as at least one of individual commands or command lines from the plurality of network device configuration files.
12. A network management system employing at least one hardware processor comprising: a network manager including the at least one hardware processor; a storage device in which the network manager stores a set of design filters; a graphical user interface through which users interact with the network manager; and a network interface through which the network manager obtains information about network devices; the network manager configured to store the set of design filters in the storage device by providing at least one input screen via the graphical user interface; receiving a design filter script via the at least one input screen, wherein the design filter script includes primitives for searching lines and paragraphs in the network device configuration files having specified attributes; converting the design filter script into an executable design filter, the executable design filter configured to implement the searching when executed; and storing at least one of the design filter script or the executable design filter in the storage device; the network manager further configured to receive, via the graphical user interface, user input identifying a selected design filter from among the set of design filters and selecting a plurality of network device configuration files; the network manager further configured to apply the selected design filter to the plurality of selected network device configuration files to produce filtered results, including the filtered results for the plurality of network device configuration files; and the network manager further configured to provide the filtered results via the graphical user interface for display on a user display device, the filtered results provided via a screen having at least two windows arranged side-by-side within the screen, each window including the filtered results associated with one of the plurality of network device configuration files, the filtered results displayed as at least one of individual commands or command lines from the plurality of network device configuration files. 17. A network management system according to claim 12 , wherein the design filter script is converted into Perl.