Basically you tell nm_CutReplace to look into a large text file and to do some processing with this file before saving it into another file. By defining rules you can tell nm_CutReplace to look for some keyword and to replace all text lines which contain this keyword. You can also tell it to look for a certain keyword and to replace all occurences of this keyword with something else you have defined beforehand in a rule. You can also tell nm_CutReplace to look for a certain keyword and to copy all lines which contain this keyword into a seperate text file, the filename of which can be predefined in another rule. Finally you can tell nm_CutReplace to look for IP addresses and to replace them with their corresponding host name (Internet connection required at least one time). For looking up IP addresses nn_CutReplace needs an Internet connection. But each resolved IP/hostname combination will be stored so that further IP look ups can be cached and network traffic can be minimized.