GNU readline is described as 'software library that provides line-editing and history capabilities for interactive programs with a command-line interface' and is an app in the OS & Utilities category. There are three alternatives to GNU readline for Linux, Mac, BSD and Windows. The best alternative is libedit, which is both free and Open Source. Other great apps like GNU readline are replxx (Free, Open Source) and Linenoise (Free, Open Source).
This is an autotool- and libtoolized port of the NetBSD Editline library (libedit). This Berkeley-style licensed command line editor library provides generic line editing, history, and tokenization functions, similar to those found in GNU Readline.