linux下的程序补丁工具diff and patch
命令： diff
NAME
diff - find differences between two files
SYNOPSIS
diff [options] from-file to-file
举例：diff -Nur program-1.0 program-2.0 > program-2.0.patch
作用，比较program-1.0 and program-2.0 生成补丁program-2.0.patch
-N 指定一个新文件
-u 统一格式的补丁
-r 递归，包括子目录和文件
命令：patch
NAME
patch - apply a diff file to an original
SYNOPSIS
patch [options] [originalfile [patchfile]]
but usually just
patch -pnum <patchfile
举例：patch program-1.0 program-2.0.patch
作用：从program-1.0 升级到 program-2.0
