Unix的隐藏文件原来一开始是个bug。。。。。。
一个bug演变成feature的经典例子。。。。。。。。。。再也不相信软件开发了!
From: https://plus.google.com/101960720994009339267/posts/R58WgWwN9jp
By Rob Pike
A lesson in shortcuts.
Long ago, as the design of the Unix file system was being worked out, the entries . and .. appeared, to make navigation easier. I'm not sure but I believe .. went in during the Version 2 rewrite, when the file system became hierarchical (it had a very different structure early on). When one typed ls, however, these files appeared, so either Ken or Dennis added a simple test to the program. It was in assembler then, but the code in question was equivalent to something like this:
if (name[0] == '.') continue;
This statement was a little shorter than what it should have been, which is
if (strcmp(name, ".") == 0 || strcmp(name, "..") == 0) continue;
but hey, it was easy.
Two things resulted.
First, a bad precedent was set. A lot of other lazy programmers introduced bugs by making the same simplification. Actual files beginning with periods are often skipped when they should be counted.
Second, and much worse, the idea of a "hidden" or "dot" file was created. As a consequence, more lazy programmers started dropping files into everyone's home directory. I don't have all that much stuff installed on the machine I'm using to type this, but my home directory has about a hundred dot files and I don't even know what most of them are or whether they're still needed. Every file name evaluation that goes through my home directory is slowed down by this accumulated sludge.
I'm pretty sure the concept of a hidden file was an unintended consequence. It was certainly a mistake.
How many bugs and wasted CPU cycles and instances of human frustration (not to mention bad design) have resulted from that one small shortcut about 40 years ago?
Keep that in mind next time you want to cut a corner in your code.
(For those who object that dot files serve a purpose, I don't dispute that but counter that it's the files that serve the purpose, not the convention for their names. They could just as easily be in $HOME/cfg or $HOME/lib, which is what we did in Plan 9, which had no dot files. Lessons can be learned.)
From: https://plus.google.com/101960720994009339267/posts/R58WgWwN9jp
By Rob Pike
A lesson in shortcuts.
Long ago, as the design of the Unix file system was being worked out, the entries . and .. appeared, to make navigation easier. I'm not sure but I believe .. went in during the Version 2 rewrite, when the file system became hierarchical (it had a very different structure early on). When one typed ls, however, these files appeared, so either Ken or Dennis added a simple test to the program. It was in assembler then, but the code in question was equivalent to something like this:
if (name[0] == '.') continue;
This statement was a little shorter than what it should have been, which is
if (strcmp(name, ".") == 0 || strcmp(name, "..") == 0) continue;
but hey, it was easy.
Two things resulted.
First, a bad precedent was set. A lot of other lazy programmers introduced bugs by making the same simplification. Actual files beginning with periods are often skipped when they should be counted.
Second, and much worse, the idea of a "hidden" or "dot" file was created. As a consequence, more lazy programmers started dropping files into everyone's home directory. I don't have all that much stuff installed on the machine I'm using to type this, but my home directory has about a hundred dot files and I don't even know what most of them are or whether they're still needed. Every file name evaluation that goes through my home directory is slowed down by this accumulated sludge.
I'm pretty sure the concept of a hidden file was an unintended consequence. It was certainly a mistake.
How many bugs and wasted CPU cycles and instances of human frustration (not to mention bad design) have resulted from that one small shortcut about 40 years ago?
Keep that in mind next time you want to cut a corner in your code.
(For those who object that dot files serve a purpose, I don't dispute that but counter that it's the files that serve the purpose, not the convention for their names. They could just as easily be in $HOME/cfg or $HOME/lib, which is what we did in Plan 9, which had no dot files. Lessons can be learned.)
热门话题 · · · · · · ( 去话题广场 )
- 被自己的直觉拯救的瞬间 新话题
- 宿命感油然而生的歌单 3264次浏览
- 道观游记 6.7万次浏览
- 来豆瓣之后你最大的收获是什么? 76.6万次浏览
- 有哪些世界观宏大或有趣的影视作品? 5.7万次浏览
- 高考复读生如何调整自己的心态? 3.2万次浏览