Many search terms take a string as a parameter and match it against one or more fields of a package. Strings can be entered either with or without double quotes (“"”), so “?name(scorch)” and “?name("scorch")” will perform the same search. If you enter a search string using double quotes, you can include a literal double-quote in the search string by placing a backslash (“\”) immediately before it: for instance, “?description("\"easy\"")” will match any package whose description contains the string “"easy"”.

If you enter a “bare” string, one not surrounded by double quotes, then aptitude will consider the string to have “ended” when it encounters the closing parenthesis or the comma before a second argument to the search term. ^[14] To remove the special meaning of these characters, place a tilde (“~”) directly before them. For instance, “?description(etc))” is a syntax error, because the first “)” ends the ?description term, and the second “)” does not correspond to any “(”. In contrast, “?description(etc~))” matches any package whose description contains the text “etc)”. There are additional considerations if you are using the shorthand notation for a term; see the section called “Shorthand for search terms” for details.

Most textual searches (for package names, descriptions, etc) are performed using case-insensitive regular expressions. A regular expression will match against a field if any portion of the field matches the expression; for instance, “ogg[0-9]” will match “libogg5”, “ogg123”, and “theogg4u”. Some characters have a special meaning within regular expressions ^[15] , so if you want to match them in searches you need to backslash-escape them: for instance, to find “g++”, you should use the pattern “g\+\+”.

The characters “!” and “|” have special meanings within search patterns. In order to include these characters in an unquoted string, you can place a tilde (“~”) directly before them. For instance, to match packages whose description contains either “grand” or “oblique”, use the pattern “?description(grand~|oblique)”. However, you will probably find it more convenient to simply use a quoted string in these cases: “?description("grand|oblique")”.