如何确定 Git 将文件处理为二进制文件还是文本文件？

How to determine if Git handles a file as binary or as text?

提问by kayahr

I know that Git somehow automatically detects if a file is binary or text and that .gitattributescan be used to set this manually if needed. But is there also a way to ask Git how it treats a file?

我知道 Git 会以某种方式自动检测文件是二进制文件还是文本文件，.gitattributes如果需要，可用于手动设置。但是还有一种方法可以询问 Git 如何处理文件吗？

So let's say I have a Git repository with two files in it: An ascii.datfile containing plain-text and a binary.datfile containing random binary stuff. Git handles the first .datfile as text and the secondary file as binary. Now I want to write a Git web front end which has a viewer for text files and a special viewer for binary files (displaying a hex dump for example). Sure, I could implement my own text/binary check but it would be more useful if the viewer relies on the information how Git handles these files.

因此，假设我有一个 Git 存储库，其中包含两个文件：一个ascii.dat包含纯文本的binary.dat文件和一个包含随机二进制内容的文件。Git 将第一个.dat文件作为文本处理，将第二个文件作为二进制文件处理。现在我想编写一个 Git Web 前端，它有一个文本文件查看器和一个特殊的二进制文件查看器（例如显示十六进制转储）。当然，我可以实现我自己的文本/二进制检查，但如果查看器依赖 Git 如何处理这些文件的信息，它会更有用。

So how can I ask Git if it treats a file as text or binary?

那么我如何询问 Git 将文件视为文本文件还是二进制文件？

采纳答案by Chris Johnsen

builtin_diff()¹calls diff_filespec_is_binary()which calls buffer_is_binary()which checks for any occurrence of a zero byte (NUL “character”) in the first 8000 bytes (or the entire length if shorter).

builtin_diff()¹调用diff_filespec_is_binary()它调用buffer_is_binary()检查前 8000 个字节（或整个长度，如果较短）中是否出现任何零字节（NUL“字符”）。

I do not see that this “is it binary?” test is explicitly exposed in any command though.

我没有看到这是“它是二进制的吗？” 但是，测试在任何命令中都明确公开。

git merge-filedirectly uses buffer_is_binary(), so you may be able to make use of it:

git merge-file直接使用buffer_is_binary()，因此您可以使用它：

git merge-file /dev/null /dev/null file-to-test

It seems to produce the error message like error: Cannot merge binary files: file-to-testand yields an exit status of 255 when given a binary file. I am not sure I would want to rely on this behavior though.

error: Cannot merge binary files: file-to-test当给定二进制文件时，它似乎会产生类似的错误消息并产生 255 的退出状态。不过，我不确定我是否想依赖这种行为。

Maybe git diff --numstatwould be more reliable:

也许git diff --numstat会更可靠：

isBinary() {
    p=$(printf '%s\t-\t' -)
    t=$(git diff --no-index --numstat /dev/null "")
    case "$t" in "$p"*) return 0 ;; esac
    return 1
}
isBinary file-to-test && echo binary || echo not binary

For binary files, the --numstatoutput should start with -TAB -TAB, so we just test for that.

对于二进制文件，--numstat输出应以-TAB -TAB开头，因此我们只进行测试。

---

---

¹builtin_diff()has strings like Binary files %s and %s differthat should be familiar.

¹builtin_diff()有这样的字符串Binary files %s and %s differ应该很熟悉。

回答by cstork

git grep -I --name-only --untracked -e . -- ascii.dat binary.dat ...

will return the names of files that git interprets as text files.

将返回 git 解释为文本文件的文件名。

You can use wildcards e.g.

您可以使用通配符，例如

git grep -I --name-only --untracked -e . -- *.ps1

回答by Seth Robertson

I don't like this answer, but you can parse the output of git-diff-tree to see if it is binary. For example:

我不喜欢这个答案，但是您可以解析 git-diff-tree 的输出以查看它是否是二进制的。例如：

git diff-tree -p 4b825dc642cb6eb9a060e54bf8d69288fbee4904 HEAD -- MegaCli 
diff --git a/megaraid/MegaCli b/megaraid/MegaCli
new file mode 100755
index 0000000..7f0e997
Binary files /dev/null and b/megaraid/MegaCli differ

as opposed to:

与：

git diff-tree -p 4b825dc642cb6eb9a060e54bf8d69288fbee4904 HEAD -- megamgr
diff --git a/megaraid/megamgr b/megaraid/megamgr
new file mode 100755
index 0000000..50fd8a1
--- /dev/null
+++ b/megaraid/megamgr
@@ -0,0 +1,78 @@
+#!/bin/sh
[…]

Oh, and BTW, 4b825d… is a magic SHA which represents the empty tree (it isthe SHA for an empty tree, but git is specially aware of this magic).

哦，顺便说一句，4b825d……是代表空树的魔术SHA（它是空树的SHA，但git特别了解这种魔术）。

回答by yoder2000

At the risk of getting slapped for poor code quality, I'm listing a C utility, is_binary, built around the original buffer_is_binary() routine in the Git source. Please see internal comments for how to build and run. Easily modifyable:

冒着因代码质量差而被打脸的风险，我列出了一个 C 实用程序 is_binary，它围绕 Git 源中的原始 buffer_is_binary() 例程构建。有关如何构建和运行，请参阅内部评论。易于修改：

/***********************************************************
 * is_binary.c 
 *
 * Usage: is_binary <pathname>
 *   Returns a 1 if a binary; return a 0 if non-binary
 * 
 * Thanks to Git and Stackoverflow developers for helping with these routines:
 * - the buffer_is_binary() routine from the xdiff-interface.c module 
 *   in git source code.
 * - the read-a-filename-from-stdin route
 * - the read-a-file-into-memory (fill_buffer()) routine
 *
 * To build:
 *    % gcc is_binary.c -o is_binary
 *
 * To build debuggable (to push a few messages to stdout):
 *    % gcc -DDEBUG=1 ./is_binary.c -o is_binary
 *
 * BUGS:
 *  Doesn't work with piped input, like 
 *    % cat foo.tar | is_binary 
 *  Claims that zero input is binary. Actually, 
 *  what should it be?
 *
 * Revision 1.4
 *
 * Tue Sep 12 09:01:33 EDT 2017
***********************************************************/
#include <string.h>
#include <stdio.h>
#include <stdlib.h>

#define MAX_PATH_LENGTH 200
#define FIRST_FEW_BYTES 8000

/* global, unfortunately */
char *source_blob_buffer;

/* From: https://stackoverflow.com/questions/14002954/c-programming-how-to-read-the-whole-file-contents-into-a-buffer */

/* From: https://stackoverflow.com/questions/1563882/reading-a-file-name-from-piped-command */

/* From: https://stackoverflow.com/questions/6119956/how-to-determine-if-git-handles-a-file-as-binary-or-as-text
*/

/* The key routine in this function is from libc: void *memchr(const void *s, int c, size_t n); */
/* Checks for any occurrence of a zero byte (NUL character) in the first 8000 bytes (or the entire length if shorter). */

int buffer_is_binary(const char *ptr, unsigned long size)
{
  if (FIRST_FEW_BYTES < size)
    size = FIRST_FEW_BYTES;
    /* printf("buff = %s.\n", ptr); */
  return !!memchr(ptr, 0, size);
}
int fill_buffer(FILE * file_object_pointer) {
  fseek(file_object_pointer, 0, SEEK_END);
  long fsize = ftell(file_object_pointer);
  fseek(file_object_pointer, 0, SEEK_SET);  //same as rewind(f);
  source_blob_buffer = malloc(fsize + 1);
  fread(source_blob_buffer, fsize, 1, file_object_pointer);
  fclose(file_object_pointer);
  source_blob_buffer[fsize] = 0;
  return (fsize + 1);
}
int main(int argc, char *argv[]) {

  char pathname[MAX_PATH_LENGTH];
  FILE *file_object_pointer;

  if (argc == 1) {
    file_object_pointer = stdin;
  } else {
    strcpy(pathname,argv[1]);
#ifdef DEBUG
    printf("pathname=%s.\n", pathname); 
#endif 
    file_object_pointer = fopen (pathname, "rb");
    if (file_object_pointer == NULL) {
      printf ("I'm sorry, Dave, I can't do that--");
      printf ("open the file '%s', that is.\n", pathname);
      exit(3);
    }
  }
  if (!file_object_pointer) {
    printf("Not a file nor a pipe--sorry.\n");
    exit (4);
  }
  int fsize = fill_buffer(file_object_pointer);
  int result = buffer_is_binary(source_blob_buffer, fsize - 2);

#ifdef DEBUG
  if (result == 1) {
    printf ("%s %d\n", pathname, fsize - 1);
  }
  else {
    printf ("File '%s' is NON-BINARY; size is %d bytes.\n", pathname, fsize - 1); 
  }
#endif
  exit(result);
  /* easy check -- 'echo $?' after running */
}

回答by Michael Freidgeim

You can use command-line tool 'file' utility. On Windows it's included in git installation and normally located in in C:\Program Files\git\usr\bin folder

您可以使用命令行工具“文件”实用程序。在 Windows 上，它包含在 git 安装中，通常位于 C:\Program Files\git\usr\bin 文件夹中

file --mime-encoding *

See more in Get encoding of a file in Windows

在 Windows中获取文件编码中查看更多信息