操作方法
1. #include<stdio.h> 2. 3. #include<sys/types.h> 4. #include<sys/stat.h> 5. #include<fcntl.h> 6. 7. #define LENGTH 100 8. 9. int main(int argc,char* argv[]) 10. { 11. int fd,len; 12. char str[LENGTH]; 13. char *content="hi!"; 14. char *path="/tmp/test.txt"; 15. if(argc<2){ 16. printf("Usage:Please pass the content as argument!\n"); 17. exit(1); 18. } 19. content=argv[1]; 20. fd=open(path,O_CREAT|O_RDWR,S_IRUSR|S_IWUSR); 21. if(fd<0){ 22. printf("Fail to open or create file!\n"); 23. exit(1); 24. } 25. if(write(fd,content,strlen(content))!=strlen(content)){ 26. printf("write error!\n"); 27. exit(1); 28. } 29. close(fd); 30. 31. if((fd=open(path,O_RDWR))<0){ 32. printf("Fail to open file!\n"); 33. exit(1); 34. } 35. if((len=read(fd,str,LENGTH))<0){ 36. printf("Read file error!\n"); 37. exit(1); 38. } 39. str[len]='\0'; 40. printf("%s\n",str); 41. close(fd); 42. return 0; 43. } 用malloc函数代替数组str，根据要打印的内容长度动态申请内存： 1. #include<stdio.h> 2. 3. #include<sys/types.h> 4. #include<sys/stat.h> 5. #include<fcntl.h> 6. 7. //#define LENGTH 100 8. 9. int main(int argc,char* argv[]) 10. { 11. int fd,len; 12. // char str[LENGTH]; 13. char *str; 14. char *content="hi!"; 15. char *path="/tmp/test.txt"; 16. if(argc<2){ 17. printf("%s\n",content); 18. printf("Usage:Please pass the content as argument!\n"); 19. exit(1); 20. } 21. content=argv[1]; 22. fd=open(path,O_CREAT|O_RDWR,S_IRUSR|S_IWUSR); 23. if(fd<0){ 24. printf("Fail to open or create file!\n"); 25. exit(1); 26. } 27. if(write(fd,content,strlen(content))!=strlen(content)){ 28. printf("write error!\n"); 29. exit(1); 30. } 31. close(fd); 32. 33. if((fd=open(path,O_RDWR))<0){ 34. printf("Fail to open file!\n"); 35. exit(1); 36. } 37. str=malloc(strlen(content)); 38. if((len=read(fd,str,strlen(content)))<0){ 39. printf("Read file error!\n"); 40. exit(1); 41. } 42. // str[len]='\0'; 43. printf("%s\n",str); 44. free(str); 45. close(fd); 46. return 0; 47. }