Interact with radare2, See the mli for documentation, example usage in utop:

#require "radare2";; let result = R2.with_command_j ~cmd:"/j COLUMNS" "/bin/ls";; val result : Yojson.t = List [Assoc [("offset", Int 109075); ("type", String "string"); ("data", `String "eQUOTING_STYLECOLUMNSTABSIZEinvalid")]; Assoc [("offset", Int 118247); ("type", String "string"); ("data", String "onment variable COLUMNS: %signori")]]"