{"id":191,"date":"2011-09-02T13:16:30","date_gmt":"2011-09-02T05:16:30","guid":{"rendered":"http:\/\/ykyi.net\/?p=191"},"modified":"2011-09-02T13:16:30","modified_gmt":"2011-09-02T05:16:30","slug":"diff-patch-and-friendsdiff-patch%e5%92%8c%e4%bb%96%e4%bb%ac%e7%9a%84%e7%9b%b8%e5%85%b3%e5%b7%a5%e5%85%b7%e7%ac%ac%e4%ba%8c%e7%af%87","status":"publish","type":"post","link":"https:\/\/ykyi.net\/?p=191","title":{"rendered":"Diff, Patch, and Friends(diff, patch\u548c\u4ed6\u4eec\u7684\u76f8\u5173\u5de5\u5177)(\u7b2c\u4e8c\u7bc7)"},"content":{"rendered":"

\u539f\u6587 http:\/\/www.linuxjournal.com\/article\/1237
\n\t\u7ffb\u8bd1: www.ykyi.net zausiu
\n\t\u63a5\u4e0a\u7bc7<\/a><\/p>\n

Use the diff program to avoid eyestrain and insanity:
\n\t\u4f7f\u7528diff\u7a0b\u5e8f\u6765\u907f\u514d\u4f1a\u4ee4\u4eba\u53d1\u75af\u7684\u8089\u773c\u67e5\u627e\u3002<\/p>\n

diff -u 1 2
\n\t— 1 Sat Apr 20 22:11:53 1996
\n\t+++ 2 Sat Apr 20 22:12:01 1996
\n\t-1,9 +1,9
\n\tEcce Eduardus Ursus scalis nunc tump-tump-tump
\n\toccipite gradus pulsante post Christophorum
\n\tRobinum descendens. Est quod sciat unus et solus
\n\t-modus gradibus desendendi, non nunquam autem
\n\t+modus gradibus descendendi, nonnunquam autem
\n\tsentit, etiam alterum modum exstare, dummodo
\n\t-pulsationibus desinere et de no modo meditari
\n\t+pulsationibus desinere et de eo modo meditari
\n\tpossit. Deinde censet alios modos non esse. En,
\n\tnunc ipse in imo est, vobis ostentari paratus.
\n\tWinnie ille Pu.<\/p>\n

There are several things to notice here:
\n\t\u8fd9\u91cc\u6709\u51e0\u4e2a\u4e1c\u897f\u8981\u63d0\u4e00\u4e0b\uff1a<\/p>\n

*<\/p>\n

The file names and last dates of modification are shown in a “header” at the top. The dates may not mean anything if you are comparing files that have been passed back and forth by e-mail, but they become very useful in other circumstances.
\n\t\u6587\u4ef6\u540d\u548c\u4e0a\u4ea4\u66f4\u65b0\u65f6\u95f4\u5728\u8f93\u51fa\u4e2d\u524d\u9762\u90e8\u5206\u663e\u793a\u3002\u5982\u679c\u4f60\u53ea\u662f\u6bd4\u8f83\u7531\u7535\u5b50\u90ae\u4ef6\u53d1\u6765\u53d1\u53bb\u7684\u6587\u4ef6\u7684\u8bdd\uff0c\u66f4\u65b0\u65f6\u95f4\u53ef\u80fd\u5e76\u4e0d\u91cd\u8981\u3002\u4f46\u662f\u5728\u67d0\u4e9b\u60c5\u51b5\u4e0b\uff0c\u786e\u5b9e\u8fd8\u662f\u5f88\u6709\u7528\u7684\u3002
\n\t*<\/p>\n

The file names (in this case, 1 and 2—are preceded by — and +++.
\n\t\u6587\u4ef6\u540d\uff08\u5728\u8fd9\u4e2a\u4f8b\u5b50\u4e2d\uff0c\u6709\u4e24\u4e2a\u6587\u4ef6\uff0c\u4e00\u4e2a\u540d\u4e3a1\uff0c\u53e6\u4e00\u4e2a\u540d\u4e3a2\uff09\u52a0\u4e0a\u4e86 — \u548c +++ \u7684\u524d\u7f00\u3002
\n\t*<\/p>\n

After the header comes a line that includes numbers. We will discuss that line later.
\n\t\u5728\u5934\u90e8\u4e4b\u540e\u6709\u4e00\u884c\u5305\u62ec\u4e86\u4e00\u4e9b\u6570\u5b57\u3002\u6211\u4eec\u5c06\u5728\u4e4b\u540e\u8ba8\u8bba\u5b83\u3002
\n\t*<\/p>\n

The lines that did not change between files are shown preceded by spaces; those that are different in the different files are shown preceded by a character which shows which file they came from. Lines which exist only in a file whose name is preceded by — in the header are preceded by a – character, and vice-versa for lines preceded by a + character. Another way to remember this is to see that the lines preceded by a – character were removed from the first (—) file, and those preceded by a + character were added to the second (+++) file.
\n\t\u6240\u6709\u6ca1\u6709\u66f4\u6539\u7684\u884c\u663e\u793a\u51fa\u6765\u65f6\u4ec5\u4ec5\u52a0\u4e0a\u7a7a\u683c\u4f5c\u524d\u7f00\u3002\u5982\u679c\u662f\u4e0d\u540c\u7684\u884c\u5462\uff0c\u5219\u5728\u6bcf\u4e00\u884c\u524d\u52a0\u4e0a\u6307\u793a\u5b83\u4eec\u51fa\u5904\u7684\u524d\u7f00\u3002\u52a0\u4e0a-\u524d\u7f00\u8868\u793a\u6765\u81ea\u5934\u90e8\u6807\u5fd7\u7684 — \u6587\u4ef6\uff0c\u5982\u679c\u52a0\u4e0a + \u524d\u7f00\u5219\u8868\u793a\u6765\u81ea\u5934\u90e8\u6807\u5fd7\u7684 +++ \u6587\u4ef6\u3002\u53e6\u5916\u4f60\u4e5f\u53ef\u4ee5\u7406\u89e3\u6210: \u6709 – \u524d\u7f00\u7684\u884c\u8868\u793a\u4ece\u7b2c\u4e00\u4e2a\u6587\u4ef6(—)\u4e2d\u5220\u9664\u4e86\uff0c\u800c\u6709 + \u524d\u7f00\u7684\u884c\u8868\u793a\u662f\u5728(+++)\u6587\u4ef6\u4e2d\u6dfb\u52a0\u7684\u3002
\n\t*<\/p>\n

Three spelling changes have been made: “desendendi” has been corrected to “descendendi”, “non nunquam” has been corrected to “nonnunquam”, and “no” has been corrected to “eo”.
\n\t\u53d1\u73b0\u4e09\u4e2a\u62fc\u5199\u6539\u52a8\u3002<\/p>\n

Perhaps the main thing to notice is that you didn't need this description of how to interpret diff's output in order to find the differences. It is rather easy to compare two adjacent lines and see the differences.
\n\t\u53ef\u80fd\u4f60\u6700\u5173\u5fc3\u7684\u4e0d\u662f\u600e\u4e48\u89e3\u6790diff\u7684\u8f93\u5165\u6765\u627e\u5230\u5206\u522b\u3002\u6bd4\u8f83\u4e24\u4e2a\u76f8\u90bb\u7684\u884c\u6765\u627e\u533a\u522b\u662f\u76f8\u5f53\u5bb9\u6613\u7684\u3002<\/p>\n

It's not always this easy
\n\t\u4f46\u4e8b\u5b9e\u4e0a\u5e76\u4e0d\u603b\u662f\u5982\u6b64\u3002<\/p>\n

Unfortunately, if too many adjacent lines have been changed, interpretation isn't as immediately obvious; but by knowing that each marked line has been changed in some way, you can figure it out. For instance, in this comparison, where the file 3 contains the damaged contents, and file 4 (identical to file 2 in the previous example) contains the correct contents, three lines in a row are changed, and now each line with a difference is not shown directly above the corrected line:
\n\t\u5f88\u4e0d\u5e78\u7684\u662f\u3002\u5982\u679c\u592a\u591a\u7684\u76f8\u90bb\u884c\u6709\u6539\u52a8\u7684\u8bdd\uff0c\u5c31\u4e0d\u662f\u90a3\u4e48\u660e\u663e\u5566\u3002\u4f46\u662f\u5982\u679c\u77e5\u9053\u6bcf\u884c\u662f\u600e\u4e48\u6539\u52a8\u7684\uff0c\u4f60\u5c31\u88ab\u8f7b\u6613\u627e\u5230\u533a\u522b\u3002\u6bd4\u5982\u8fd9\u4e2a\u4f8b\u5b50\uff0c\u6587\u4ef63\u5305\u542b\u4e86\u53d7\u635f\u7684\u5185\u5bb9\uff0c\u800c\u6587\u4ef64(\u5176\u5b9e\u548c\u4e0a\u4e2a\u4f8b\u5b50\u4e2d\u7684\u6587\u4ef62\u4e00\u6a21\u4e00\u6837)\u5305\u542b\u4e86\u6b63\u786e\u7684\u5185\u5bb9\uff0c\u8fde\u7eed\u4e09\u884c\u88ab\u6539\u53d8\u4e86\uff0c\u73b0\u5728\u6bcf\u4e2a\u6709\u6539\u52a8\u7684\u884c\u6ca1\u6709\u5728\u6b63\u786e\u7684\u884c\u4e0a\u9762\u76f4\u63a5\u663e\u793a\u51fa\u6765\u3002<\/p>\n

diff -u 3 4
\n\t— 3 Sun Apr 21 18:57:08 1996
\n\t+++ 4 Sun Apr 21 18:56:45 1996
\n\t-1,9 +1,9
\n\tEcce Eduardus Ursus scalis nunc tump-tump-tump
\n\toccipite gradus pulsante post Christophorum
\n\tRobinum descendens. Est quod sciat unus et solus
\n\t-modus gradibus desendendi, non nunquam autem
\n\t-sentit, etiam alterum nodum exitare, dummodo
\n\t-pulsationibus desinere et de no modo meditari
\n\t+modus gradibus descendendi, nonnunquam autem
\n\t+sentit, etiam alterum modum exstare, dummodo
\n\t+pulsationibus desinere et de eo modo meditari
\n\tpossit. Deinde censet alios modos non esse. En,
\n\tnunc ipse in imo est, vobis ostentari paratus.
\n\tWinnie ille Pu.<\/p>\n

It takes a little more work to find the added mistakes; “nodum” for “modum” and “exitare” for “exstare”. Imagine if 50 lines in a row had each had a one-character change, though. This begins to resemble the old job of going through the whole file, character-by-character, looking for changes. All we've done is (potentially) shrink the amount of comparison you have to do.
\n\t\u8fd9\u5c31\u9700\u8981\u82b1\u8d39\u66f4\u591a\u7684\u5de5\u4f5c\u6765\u627e\u5230\u9519\u8bef\u5566\u3002“nodum” for “modum” and “exitare” for “exstare”\u3002\u60f3\u8c61\u4e00\u4e0b\uff0c\u5982\u679c\u8fde\u7eed50\u884c\uff0c\u6bcf\u884c\u90fd\u6709\u4e00\u4e2a\u5b57\u6bcd\u7684\u6539\u53d8\uff0c\u90a3\u4e48\u4f60\u8981\u505a\u7684\u5de5\u4f5c\u53c8\u548c\u4f7f\u7528diff\u524d\u4e00\u6837\u561e\u3002\u9010\u5b57\u9010\u5b57\u7684\u67e5\u627e\uff01diff\u4ec5\u4ec5\u5e2e\u4f60\u628a\u66f4\u6539\u8303\u56f4\u9650\u5b9a\u4e86\u800c\u5df2\u3002<\/p>\n

Fortunately, there are several tools for finding these kinds of differences more easily. GNU Emacs has “word diff” functionality. There is also a GNU “wdiff” program which helps you find these kinds of differences without using Emacs.
\n\t\u597d\u6709\u597d\u4e9b\u5de5\u5177\u5e2e\u52a9\u4f60\u5f88\u5bb9\u6613\u5b9a\u4f4d\u5230\u8fd9\u4e9b\u5dee\u5f02\u3002GNU Emacs\u5c31\u6709\u4e00\u4e2a"word diff"\u7684\u529f\u80fd\u3002\u8fd8\u6709\u4e00\u4e2a\u53ebwdiff\u7684GNU\u5de5\u5177\u4e5f\u80fd\u5e2e\u52a9\u4f60\u67e5\u627e\u8fd9\u79cd\u7c7b\u578b\u7684\u9519\u8bef\u3002<\/p>\n

Let's look first at GNU Emacs. For this example, files 5 and 6 are exactly the same, respectively, as files 3 and 4 before. I bring up emacs under X (which provides me with colored text), and type:
\n\t\u8ba9\u6211\u4eec\u5148\u770b\u770bGNU Emacs\u3002<\/p>\n

M-x ediff-files RET
\n\t5 RET
\n\t6 RET<\/p>\n

In the new window which pops up, I press the space bar, which tells Emacs to highlight the differences. Look at Figure 1 and see how easy it is to find each changed word.<\/p>\n

Figure 1. ediff-files 5 6<\/p>\n

GNU wdiff is also very useful, especially if you aren't running X. A pager (such as less) is all that is required—and that is only required for large differences. The exact same set of files (5 and 6), compared with the command wdiff -t 5 6, is shown in Figure 2.
\n\tGNU wdiff\u4e5f\u5f88\u6709\u7528\uff0c\u7279\u522b\u662f\u4f60\u6ca1\u6709\u8fd0\u884cX\u670d\u52a1\u7684\u65f6\u5019\u3002\u4e00\u4e2a\u5206\u5c4f\u5de5\u5177(\u6bd4\u5982 less)\u5c31\u8db3\u591f\u7528\u6765\u67e5\u627e\u5927\u8303\u56f4\u7684\u5dee\u5f02\u4e86\u3002<\/p>\n

Figure 2. wdiff -t 5 6<\/p>\n

\/\/\/\/\/\/\/
\n\t\u597d\u8f9b\u82e6\u3002\u4e0d\u60f3\u8bd1\u4e86~~\u4e0d\u8bd1\u4e86\u3002\u81ea\u5df1\u53bb\u770b\u539f\u6587\u5427\u3002\u7d2f\u6b7b\u54e5\u4e86\u3002<\/p>\n

copyright ykyi.net<\/p>\n","protected":false},"excerpt":{"rendered":"

\u539f\u6587 http:\/\/www.linuxjournal.com\/article\/1237 \u7ffb\u8bd1: www.ykyi.net zausiu \u63a5\u4e0a\u7bc7 Use the diff program to avoid eyestrain and insanity: \u4f7f\u7528diff\u7a0b\u5e8f\u6765\u907f\u514d\u4f1a\u4ee4\u4eba\u53d1\u75af\u7684\u8089\u773c\u67e5\u627e\u3002 diff -u 1 2 — 1 Sat Apr 20 22:11:53 1996 +++ 2 Sat Apr 20 22:12:01 1996 -1,9 +1,9 Ecce Eduardus Ursus scalis nunc tump-tump-tump occipite gradus pulsante post Christophorum Robinum descendens. Est quod sciat unus et solus … Continue reading “Diff, Patch, and Friends(diff, patch\u548c\u4ed6\u4eec\u7684\u76f8\u5173\u5de5\u5177)(\u7b2c\u4e8c\u7bc7)”<\/span><\/a><\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[6,7],"tags":[28,83],"class_list":["post-191","post","type-post","status-publish","format-standard","hentry","category-tech_articles","category-unix_linux","tag-diff","tag-unix-tools"],"_links":{"self":[{"href":"https:\/\/ykyi.net\/index.php?rest_route=\/wp\/v2\/posts\/191","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/ykyi.net\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/ykyi.net\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/ykyi.net\/index.php?rest_route=\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/ykyi.net\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=191"}],"version-history":[{"count":0,"href":"https:\/\/ykyi.net\/index.php?rest_route=\/wp\/v2\/posts\/191\/revisions"}],"wp:attachment":[{"href":"https:\/\/ykyi.net\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=191"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/ykyi.net\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=191"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/ykyi.net\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=191"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}