[英]How to read all files in a folder using C
I wish to read all the text files in a particular folder.我希望阅读特定文件夹中的所有文本文件。 The files' names do not have any common pattern in them- else the task would have been easier.文件的名称中没有任何通用模式——否则任务会更容易。
//read a file from the directory
//Perform a common operation
//write output to a common file
//read the next file
It will be good if I could work around with sub-folders as well, but even the basic implementation is sufficient.如果我也可以处理子文件夹就好了,但即使是基本实现也足够了。
I tried looking at the previously asked related questions ( here , here , here and here ), but none of them give a C and Linux specific answer which I need.我尝试查看之前提出的相关问题(此处、此处、此处和此处),但没有一个给出我需要的 C 和 Linux 特定答案。
edit : So, this is what I wrote based on the answers received-编辑:所以,这是我根据收到的答案写的-
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <sys/types.h>
#include <dirent.h>
#include <unistd.h>
#include <errno.h>
int main(int argc, char **argv)
{
DIR* FD;
struct dirent* in_file;
FILE *output_file;
FILE *entry_file;
char buffer[BUFSIZ];
/* Opening common file for writing */
output_file = fopen("/home/pnp/snort_rules_folder/rulesoutput.txt", "a+");
if (output_file == NULL)
{
fprintf(stderr, "Error : Failed to open output_file\n");
return 1;
}
/* Scanning the in directory */
if (NULL == (FD = opendir ("/home/pnp/snort_rules_folder/rules")))
{
fprintf(stderr, "Error : Failed to open input directory\n");
fclose(output_file);
return 1;
}
while ((in_file = readdir(FD)))
{
/* On linux/Unix we don't want current and parent directories
* If you're on Windows machine remove this two lines
*/
if (!strcmp (in_file->d_name, "."))
continue;
if (!strcmp (in_file->d_name, ".."))
continue;
/* Open directory entry file for common operation */
/* TODO : change permissions to meet your need! */
entry_file = fopen(in_file->d_name, "r");
if (entry_file == NULL)
{
fprintf(stderr, "Error : Failed to open entry file\n");
fclose(output_file);
return 1;
}
/* Doing some stuff with entry_file : */
while (fgets(buffer, BUFSIZ, entry_file) != NULL)
{
/* Use fprintf or fwrite to write some stuff into common_file*/
}
fprintf(output_file, "reading file %s", in_file->d_name);
/* When you finish with the file, close it */
fclose(entry_file);
}
/* Don't forget to close common file before leaving */
fclose(output_file);
return 0;
}
And the error received-和收到的错误 -
pnp@pnp-laptop:~/snort_rules_folder$ ./a.out pnp@pnp-laptop:~/snort_rules_folder$ ./a.out
Error : Failed to open entry file错误:无法打开入口文件
You can use this sample code and modify it if you need:您可以使用此示例代码并根据需要对其进行修改:
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <sys/types.h>
#include <dirent.h>
#include <unistd.h>
#include <errno.h>
/* This is just a sample code, modify it to meet your need */
int main(int argc, char **argv)
{
DIR* FD;
struct dirent* in_file;
FILE *common_file;
FILE *entry_file;
char buffer[BUFSIZ];
/* Openiing common file for writing */
common_file = fopen(path_to_your_common_file, "w");
if (common_file == NULL)
{
fprintf(stderr, "Error : Failed to open common_file - %s\n", strerror(errno));
return 1;
}
/* Scanning the in directory */
if (NULL == (FD = opendir (in_dir)))
{
fprintf(stderr, "Error : Failed to open input directory - %s\n", strerror(errno));
fclose(common_file);
return 1;
}
while ((in_file = readdir(FD)))
{
/* On linux/Unix we don't want current and parent directories
* On windows machine too, thanks Greg Hewgill
*/
if (!strcmp (in_file->d_name, "."))
continue;
if (!strcmp (in_file->d_name, ".."))
continue;
/* Open directory entry file for common operation */
/* TODO : change permissions to meet your need! */
entry_file = fopen(in_file->d_name, "rw");
if (entry_file == NULL)
{
fprintf(stderr, "Error : Failed to open entry file - %s\n", strerror(errno));
fclose(common_file);
return 1;
}
/* Doing some struf with entry_file : */
/* For example use fgets */
while (fgets(buffer, BUFSIZ, entry_file) != NULL)
{
/* Use fprintf or fwrite to write some stuff into common_file*/
}
/* When you finish with the file, close it */
fclose(entry_file);
}
/* Don't forget to close common file before leaving */
fclose(common_file);
return 0;
}
Hope this hellp.希望这会有所帮助。
Regards.问候。
These should get you started: 这些应该让你开始:
See other C IO functions. 请参阅其他C IO功能。
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