Linux diff比较两个目录的不同:
diff dir1 dir2 -urNaq
-a --text Treat all files as text.
-u -U NUM --unified[=NUM] Output NUM (default 3) lines of unified[统一] context.
-u，-U<列数>或–unified=<列数>：以合并的方式来显示文件内容的不同；
-N --new-file Treat absent[缺少] files as empty.
-r --recursive Recursively compare any subdirectories found.
-q --brief Output only whether files differ.[不显示内容]