ls | grep .txt | xargs cat IN C

gistfile1.c

#include <dirent.h>
#include <stdio.h>
#include <string.h>
#include <fcntl.h>
#include <sys/stat.h>
#include <stdlib.h>
#include <sys/mman.h>
#include <sys/types.h>
#include <unistd.h>

int ends_with(const char *str, const char *suffix);

int main(int argc,char **argv) {
  if (argc != 2) printf("./ex7 FOLDER");
  DIR *dirp;
  dirp = opendir(argv[1]);
  struct dirent *dptr;
  while(dptr=readdir(dirp)) {
    char fullpath[1024];
    strcpy(fullpath,argv[1]);
    strcat(fullpath,"/");
    strcat(fullpath,dptr->d_name);
    if (ends_with(fullpath,".txt")) {
      printf("FILE:%s\n",fullpath);
        int fd = open(fullpath,O_RDONLY);
        struct stat s;
        fstat(fd,&s);
        char *buffer = mmap(0,s.st_size,PROT_READ,MAP_PRIVATE,fd,0);
	printf("%s",buffer);
        close(fd);
    }
  }
  closedir(dirp);	
}

int ends_with(const char *str, const char *suffix) {
  if (!str || !suffix) return 0;
  size_t lenstr = strlen(str);
  size_t lensuffix = strlen(suffix);
  if (lensuffix >  lenstr) return 0;
  return strncmp(str + lenstr - lensuffix, suffix, lensuffix) == 0;
}