认识
官网：http://www.greenwoodsoftware.com/less/
文档：man less
仓库：http://www.greenwoodsoftware.com/less/download.html
Less is a free, open-source file pager. It can be found on most versions of Linux, Unix and Mac OS, as well as on many other operating systems.
组成
包含的可执行程序
less – opposite of more —— A file viewer or pager; it displays the contents of the given file, letting the user scroll, find strings, and jump to marks
lessecho, Needed to expand meta-characters, such as * and ?, in filenames on Unix systems
lesskey, Used to specify the key bindings for less
构建
apt-get install less
应用
显示行号 -N –LINE-NUMBERS