fx

fx can work in two modes, cli and interactive. To start interactive mode pipe any JSON into fx. One of the frequent operations is mapping some function on an array. You can pass any number of anonymous functions for reducing JSON. fx provides a function save which will save everything in place and return saved object. This function can be only used with filename as first argument to fx command. Create .fxrc file in $HOME directory, and require any packages or define global functions. To be able require global modules make sure you have correct NODE_PATH env variable. If you need output other than JSON (for example arguments for xargs), do not return anything from the reducer. undefined value is printed into stderr by default. Sometimes it is necessary to omit some messages in JSON stream, or select only specified log messages. For this purpose, fx has special helpers select/filter, pass function into it to select/filter JSON messages.