linenoise
redis-cli的实现依赖于linenoise,除此之外,使用linenoise我们可以构建自己的server的command line interface。
linenoise
A small self-contained alternative to readline and libedit.
The API
The library returns a buffer with the line composed by the user, or NULL on end of file or when there is an out of memory condition.
NOTE: 这段话怎么理解?