名字

diff - 找出兩個文件的不同點  

總覽

diff [選項] 源文件 目標文件  

描述

在最簡單的情況是, diff 比較兩個文件的內容 （源文件 和 目標文件）. 文件名可以是 - 由標準輸入設備讀入的文本. 作為特別的情況是, diff - - 比較一份標準輸入的它自己的拷貝如果 源文件 是一個目錄和 目標文件 不是（目錄）, diff 會比較在 源文件（目錄） 里的文件的中和 目標文件同名的（文件）, 反過來也一樣. 非目錄文件不能是 -. 如果 源文件 和 目標文件 都是目錄, diff 比較兩個目錄中相應的文件，依照字母次序排序；這個比較是不會遞歸的，除非給出 -r 或者 --recursive. diff 不把一個目錄的內容看為它是一個文件來比較。被指定的文件不能是標準的輸入, 因為標準的輸入是無名的并且＂有一樣的名字的文件＂的觀點不適用。 diff 的選項由 -, 開始所以正常地 源文件（名） 和 目標文件（名） 不可以用 - 開頭. 然而, -- 可以被它視為保留的即使作為文件名的開頭（ they begin with -.）  

選項

下面是 GNU所接受的 diff 的所有選項的概要. 大多數的選項有兩個相同的名字,一個是單個的跟在 - 后面字母, 另一個是由 -- 引出的長名字. 多個單字母選項（除非它們產生歧義）能夠組合為單行的命令行語法 -ac 是等同于 -a -c. 長命名的選項能被縮短到他們的名字的任何唯一的前綴. 用 ([ 和 ]) 括起來顯示選項產生歧義的選項

-行數（一個整數）

顯示上下文 行數 (一個整數). 這個選項自身沒有指定輸出格式，這是沒有效果的，除非和 -c 或者 -u 組合使用. 這是已廢置的選項，對于正確的操作, 上下文至少要有兩行。

-a

所有的文件都視為文本文件來逐行比較，甚至他們似乎不是文本文件.

-b

忽略空格引起的變化.

-B

忽略插入刪除空行引起的變化.

--brief

僅報告文件是否相異,在乎差別的細節.

-c

使用上下文輸出格式.

-C 行數（一個整數）

--context[=lines]

使用上下文輸出格式，顯示以指定 行數 (一個整數), 或者是三行（當 行數 沒有給出時. 對于正確的操作, 上下文至少要有兩行.

--changed-group-format=format

使用 format 輸出一組包含兩個文件的不同處的行，其格式是 if-then-else .

-d

改變算法也許發現變化的一個更小的集合.這會使 diff 變慢 (有時更慢).

-D name

合并 if-then-else 格式輸出, 預處理宏（由name參數提供）條件.

-e

--ed

輸出為一個有效的 ed 腳本.

--exclude=pattern

比較目錄的時候，忽略和目錄中與 pattern（樣式） 相配的.

--exclude-from=file

比較目錄的時候，忽略和目錄中與任何包含在 file（文件） 的樣式相配的文件和目錄.

--expand-tabs

在輸出時擴展tab為空格，保護輸入文件的tab對齊方式

-f

產生一個很象 ed 腳本的輸出，但是但是在他們在文件出現的順序有改變

-F regexp

在上下文和統一格式中，對于每一大塊的不同，顯示出匹配 regexp. 的一些前面的行.

--forward-ed

產生象 ed 腳本的輸出，但是它們在文件出現的順序有改變。

-h

這選項現在已沒作用，它呈現Unix的兼容性.

-H

使用啟發規則加速操作那些有許多離散的小差異的大文件.

--horizon-lines=lines

比較給定行數的有共同前綴的最后行，和有共同或綴的最前行.

-i

忽略大小寫.

-I regexp

忽略由插入，刪除行（由regexp 參數提供參考）帶來的改變.

--ifdef=name

合并 if-then-else 格式輸出, 預處理宏（由name參數提供）條件.

--ignore-all-space

在比較行的時候忽略空白.

--ignore-blank-lines

忽略插入和刪除空行

--ignore-case

忽略大小寫.

--ignore-matching-lines=regexp

忽略插入刪除行（由regexp 參數提供參考）.

--ignore-space-change

忽略空白的數量.

--initial-tab

在文本行（無論是常規的或者格式化的前后文關系）前輸出tab代替空格. 引起的原因是tab對齊方式看上去象是常規的一樣.

-l

產生通過 pr 編碼的輸出.

-L label

--label=label

使用 label 給出的字符在文件頭代替文件名輸出.

--left-column

以并列方式印出兩公共行的左邊

--line-format=format

使用 format 輸出所有的行，在 if-then-else 格式中.

--minimal

改變算法也許發現變化的一個更小的集合.這會使 diff 變慢 (有時更慢).

-n

輸出 RC-格式 diffs; 除了每條指令指定的行數受影響外 象 -f 一樣。

-N

--new-file

在目錄比較中，如果那個文件只在其中的一個目錄中找到，那么它被視為在另一個目錄中是一個空文件.

--new-group-format=format

使用 format 以if-then-else 格式輸出只在第二個文件中取出的一個行組

--new-line-format=format

使用 format 以if-then-else 格式輸出只在第二個文件中取出的一行

--old-group-format=format

使用 format 以if-then-else 格式輸出只在第一個文件中取出的一個行組

--old-line-format=format

使用 format 使用 format 以if-then-else 格式輸出只在第一個文件中取出的一行

-p

顯示帶有c函數的改變.

-P

在目錄比較中，如果那個文件只在其中的一個目錄中找到，那么它被視為在另一個目錄中是一個空文件.

--paginate

產生通過 pr 編碼的輸出.

-q

僅報告文件是否相異,不報告詳細的差異.

-r

當比較目錄時，遞歸比較任何找到的子目錄.

--rcs

輸出 RC-格式 diffs; 除了每條指令指定的行數受影響外 象 -f 一樣。

--recursive

當比較目錄時，遞歸比較任何找到的子目錄.

--report-identical-files

-s

報告兩個文件相同.

-S file

當比較目錄時，由 file 開始. 這用于繼續中斷了的比較.

--sdiff-merge-assist

打印附加的信息去幫助 sdiff. sdiff 在運行 diff 時使用這些選項. 這些選項不是特意為使用者直接使用而準備的。

--show-c-function

顯示帶有c函數的改變.

--show-function-line=regexp

在上下文和統一的格式，對于每一大塊的差別，顯示出匹配 regexp. 的一些前面的行

--side-by-side

使用并列的輸出格式.

--speed-large-files

使用啟發規則加速操作那些有許多離散的小差異的大文件.

--starting-file=file

當比較目錄時，由 file 開始. 這用于繼續中斷了的比較.

--suppress-common-lines

在并列格式中不印出公共行。

-t

在輸出時擴展tab為空格，保護輸入文件的tab對齊方式

-T

在文本行（無論是常規的或者格式化的前后文關系）前輸出tab代替空格.引起的原因是tab對齊方式看上去象是常規的一樣.

--text

所有的文件都視為文本文件來逐行比較，甚至他們似乎不是文本文件.

-u

使用統一的輸出格式.

--unchanged-group-format=format

使用 format 輸出兩個文件的公共行組，其格式是if-then-else.

--unchanged-line-format=format

使用 format 輸出兩個文件的公共行，其格式是if-then-else.

--unidirectional-new-file

在目錄比較中，如果那個文件只在其中的一個目錄中找到，那么它被視為在另一個目錄中是一個空文件.

-U lines

--unified[=lines]

使用前后關系格式輸出，顯示以指定 行數 (一個整數), 或者是三行（當 行數 沒有給出時. 對于正確的操作, 上下文至少要有兩行.

-v

--version

輸出 diff 版本號.

-w

在比較行時忽略空格

-W columns

--width=columns

在并列格式輸出時，使用指定的列寬.

-x pattern

比較目錄的時候，忽略和目錄中與 pattern（樣式） 相配的.

-X file

比較目錄的時候，忽略和目錄中與任何包含在 file（文件） 的樣式相配的文件和目錄.

-y

使用并列格式輸出

參考

cmp(1), comm(1), diff3(1), ed(1), patch(1), pr(1), sdiff(1).  

#p#

NAME

diff - find differences between two files 

SYNOPSIS

diff [options] from-file to-file  

DESCRIPTION

In the simplest case, diff compares the contents of the two files from-file and to-file. A file name of - stands for text read from the standard input. As a special case, diff - - compares a copy of standard input to itself.

If from-file is a directory and to-file is not, diff compares the file in from-file whose file name is that of to-file, and vice versa. The non-directory file must not be -.

If both from-file and to-file are directories, diff compares corresponding files in both directories, in alphabetical order; this comparison is not recursive unless the -r or --recursive option is given. diff never compares the actual contents of a directory as if it were a file. The file that is fully specified may not be standard input, because standard input is nameless and the notion of ``file with the same name'' does not apply.

diff options begin with -, so normally from-file and to-file may not begin with -. However, -- as an argument by itself treats the remaining arguments as file names even if they begin with -.  

Options

Below is a summary of all of the options that GNU diff accepts. Most options have two equivalent names, one of which is a single letter preceded by -, and the other of which is a long name preceded by --. Multiple single letter options (unless they take an argument) can be combined into a single command line word: -ac is equivalent to -a -c. Long named options can be abbreviated to any unique prefix of their name. Brackets ([ and ]) indicate that an option takes an optional argument.

-lines

Show lines (an integer) lines of context. This option does not specify an output format by itself; it has no effect unless it is combined with -c or -u. This option is obsolete. For proper operation, patch typically needs at least two lines of context.

-a

Treat all files as text and compare them line-by-line, even if they do not seem to be text.

-b

Ignore changes in amount of white space.

-B

Ignore changes that just insert or delete blank lines.

--brief

Report only whether the files differ, not the details of the differences.

-c

Use the context output format.

-C lines

--context[=lines]

Use the context output format, showing lines (an integer) lines of context, or three if lines is not given. For proper operation, patch typically needs at least two lines of context.

--changed-group-format=format

Use format to output a line group containing differing lines from both files in if-then-else format.

-d

Change the algorithm to perhaps find a smaller set of changes. This makes diff slower (sometimes much slower).

-D name

Make merged if-then-else format output, conditional on the preprocessor macro name.

-e

--ed

Make output that is a valid ed script.

--exclude=pattern

When comparing directories, ignore files and subdirectories whose basenames match pattern.

--exclude-from=file

When comparing directories, ignore files and subdirectories whose basenames match any pattern contained in file.

--expand-tabs

Expand tabs to spaces in the output, to preserve the alignment of tabs in the input files.

-f

Make output that looks vaguely like an ed script but has changes in the order they appear in the file.

-F regexp

In context and unified format, for each hunk of differences, show some of the last preceding line that matches regexp.

--forward-ed

Make output that looks vaguely like an ed script but has changes in the order they appear in the file.

-h

This option currently has no effect; it is present for Unix compatibility.

-H

Use heuristics to speed handling of large files that have numerous scattered small changes.

--horizon-lines=lines

Do not discard the last lines lines of the common prefix and the first lines lines of the common suffix.

-i

Ignore changes in case; consider upper- and lower-case letters equivalent.

-I regexp

Ignore changes that just insert or delete lines that match regexp.

--ifdef=name

Make merged if-then-else format output, conditional on the preprocessor macro name.

--ignore-all-space

Ignore white space when comparing lines.

--ignore-blank-lines

Ignore changes that just insert or delete blank lines.

--ignore-case

Ignore changes in case; consider upper- and lower-case to be the same.

--ignore-matching-lines=regexp

Ignore changes that just insert or delete lines that match regexp.

--ignore-space-change

Ignore changes in amount of white space.

--initial-tab

Output a tab rather than a space before the text of a line in normal or context format. This causes the alignment of tabs in the line to look normal.

-l

Pass the output through pr to paginate it.

-L label

--label=label

Use label instead of the file name in the context format and unified format headers.

--left-column

Print only the left column of two common lines in side by side format.

--line-format=format

Use format to output all input lines in in-then-else format.

--minimal

Change the algorithm to perhaps find a smaller set of changes. This makes diff slower (sometimes much slower).

-n

Output RCS-format diffs; like -f except that each command specifies the number of lines affected.

-N

--new-file

In directory comparison, if a file is found in only one directory, treat it as present but empty in the other directory.

--new-group-format=format

Use format to output a group of lines taken from just the second file in if-then-else format.

--new-line-format=format

Use format to output a line taken from just the second file in if-then-else format.

--old-group-format=format

Use format to output a group of lines taken from just the first file in if-then-else format.

--old-line-format=format

Use format to output a line taken from just the first file in if-then-else format.

-p

Show which C function each change is in.

-P

When comparing directories, if a file appears only in the second directory of the two, treat it as present but empty in the other.

--paginate

Pass the output through pr to paginate it.

-q

Report only whether the files differ, not the details of the differences.

-r

When comparing directories, recursively compare any subdirectories found.

--rcs

Output RCS-format diffs; like -f except that each command specifies the number of lines affected.

--recursive

When comparing directories, recursively compare any subdirectories found.

--report-identical-files

-s

Report when two files are the same.

-S file

When comparing directories, start with the file file. This is used for resuming an aborted comparison.

--from-file=file

Compare file to all operands. file can be a directory.

--to-file=file

Compare all operands to file. file can be a directory.

--sdiff-merge-assist

Print extra information to help sdiff. sdiff uses this option when it runs diff. This option is not intended for users to use directly.

--show-c-function

Show which C function each change is in.

--show-function-line=regexp

In context and unified format, for each hunk of differences, show some of the last preceding line that matches regexp.

--side-by-side

Use the side by side output format.

--speed-large-files

Use heuristics to speed handling of large files that have numerous scattered small changes.

--starting-file=file

When comparing directories, start with the file file. This is used for resuming an aborted comparison.

--suppress-common-lines

Do not print common lines in side by side format.

-t

Expand tabs to spaces in the output, to preserve the alignment of tabs in the input files.

-T

Output a tab rather than a space before the text of a line in normal or context format. This causes the alignment of tabs in the line to look normal.

--text

Treat all files as text and compare them line-by-line, even if they do not appear to be text.

-u

Use the unified output format.

--unchanged-group-format=format

Use format to output a group of common lines taken from both files in if-then-else format.

--unchanged-line-format=format

Use format to output a line common to both files in if-then-else format.

--unidirectional-new-file

When comparing directories, if a file appears only in the second directory of the two, treat it as present but empty in the other.

-U lines

--unified[=lines]

Use the unified output format, showing lines (an integer) lines of context, or three if lines is not given. For proper operation, patch typically needs at least two lines of context.

-v

--version

Output the version number of diff.

-w

Ignore white space when comparing lines.

-W columns

--width=columns

Use an output width of columns in side by side format.

-x pattern

When comparing directories, ignore files and subdirectories whose basenames match pattern.

-X file

When comparing directories, ignore files and subdirectories whose basenames match any pattern contained in file.

-y

Use the side by side output format.

SEE ALSO

cmp(1), comm(1), diff3(1), ed(1), patch(1), pr(1), sdiff(1).