bb:tldr:cee23

The command echo "{:key 'val}" | bb -I "(:key (first *input*))" consists of two parts connected by a pipe |.

1. echo "{:key 'val}":

   • The echo command is used to print the given string or value.
   • In this case, the string being echoed is "{:key 'val}", which represents a Clojure map with a single key-value pair. The key is :key, and the value is the symbol 'val.

2. bb -I "(:key (first *input*))":

   • bb is a command-line utility for working with Clojure code from the command line.
   • The -I flag specifies an expression to evaluate using bb.
   • In this case, the expression being evaluated is (:key (first *input*)). This expression takes the first element of the input provided to bb, and then accesses the value associated with the :key key in that element.
   • The input is obtained from the echo command through the pipe |. So, the output from echo (i.e., "{:key 'val}") is used as the input for bb.
   • The output of bb will be the value associated with the :key key in the input map. In this case, it will be the symbol 'val.