How to extract filename from path

Question

There should be something elegant in Linux API/POSIX to extract base file name from full path

Answer 1

You can escape slashes to backslash and use this code:

#include <stdio.h>
#include <string.h>

int main(void)
{
  char path[] = "C:\\etc\\passwd.c"; //string with escaped slashes
  char temp[256]; //result here
  char *ch; //define this
  ch = strtok(path, "\\"); //first split
  while (ch != NULL) {
      strcpy(temp, ch);//copy result
      printf("%s\n", ch);
      ch = strtok(NULL, "\\");//next split
  }

  printf("last filename: %s", temp);//result filename

  return 0;

}

Answer 2

My example (improved):

    #include <string.h>

    const char* getFileNameFromPath(const char* path, char separator = '/')
    {
        if(path != nullptr)
        {
            for(size_t i = strlen(path);  i > 0; --i)
            {
                if (path[i-1] == separator)
                {
                    return &path[i];
                }
            }
        }
    
        return path;
    }

Answer 3

The basename() function returns the last component of a path, which could be a folder name and not a file name. There are two versions of the basename() function: the GNU version and the POSIX version.

The GNU version can be found in string.h after you include #define _GNU_SOURCE:

    #define _GNU_SOURCE

    #include <string.h>

The GNU version uses const and does not modify the argument.

    char * basename (const char *path)

This function is overridden by the XPG (POSIX) version if libgen.h is included.

    char * basename (char *path)

This function may modify the argument by removing trailing '/' bytes. The result may be different from the GNU version in this case:

    basename("foo/bar/")

will return the string "bar" if you use the XPG version and an empty string if you use the GNU version.

References:

basename (3) - Linux Man Pages

Function: char * basename (const char *filename), Finding Tokens in a String.

Answer 4

See char *basename(char *path).

Or run the command "man 3 basename" on your target UNIX/POSIX system.