sentences:  In word processors, templates are a common feature, while automatic filling in of the templates is often referred to as mail merge.An illustrative example of the complementary nature of parsing and templating is the codice_1 (substitute) command in the sed text processor, originating from search-and-replace in the ed text editor.Substitution commands are of the form codice_2, where codice_3 is a regular expression, for parsing input, and codice_4 is a simple template for output, either literal text, or a format string containing the characters codice_5 for "entire match" or the special escape sequences codice_6 through codice_7 for the "n"th sub-expression.