In this book, you will find a number of text styles that distinguish between different kinds of information. Here are some examples of these styles and an explanation of their meaning.

Code words in text, database table names, folder names, filenames, file extensions, pathnames, dummy URLs, user input, and Twitter handles are shown as follows: "In a sharded environment, each mongod applies its own locks, thus greatly improving concurrency."

A block of code is set as follows:

db.account.find( { "balance" : { $type : 16 } } );
db.account.find( { "balance" : { $type : "integer" } } );

Any command-line input or output is written as follows:

> db.types.insert({"a":4})
WriteResult({ "nInserted" : 1 })

Bold: Indicates a new term, an important word, or words that you see onscreen. For example, words in menus or dialog boxes appear in the text like this. Here is an example: "The following screenshot shows the Zone configuration summary:"