自己实现more命令

 1 #include    <stdio.h>
 2 #include    <stdlib.h>
 3 
 4 #define PAGELEN 24
 5 #define LINELEN 512
 6 
 7 int see_more(FILE*);
 8 void do_more(FILE*);
 9 
10 int main(int ac, char* av[])
11 {
12     FILE *fp;
13     if(ac==1)
14         do_more(stdin);
15     //    printf("%s","Please input file name.
");
16     else
17     {    
18         while(--ac)
19         if((fp=fopen(*++av,"r"))!=NULL)
20         {
21             do_more(fp);
22             fclose(fp);    
23         }
24     }
25     
26             
27 }
28 
29 void do_more(FILE* fp)
30 {
31     int num_of_lines=0;
32     char line[LINELEN];
33     int reply;
34 //    int see_more();
35     FILE* fp_tty;
36     fp_tty=fopen("/dev/tty","r");
37     if(fp_tty==NULL) exit(1);
38     while(fgets(line,LINELEN,fp))
39     {
40         if(num_of_lines==PAGELEN)
41         {
42             reply=see_more(fp_tty);
43             if(reply==0)
44                 break;
45             num_of_lines-=reply;
46         }
47         if(fputs(line,stdout)==EOF)
48             exit(1);
49         num_of_lines++;    
50     }
51 
52 }
53 
54 int see_more(FILE* cmd)
55 {
56     int c;
57     //printf("33[7m more? 33[m");
58     printf("33[32;49;1m [more?] 33[39;49;0m");
59     //033[32;49;1m [MORE?] 33[39;49;0m
60     while((c=getc(cmd))!=EOF)
61     {
62         if(c=='q')
63             return 0;
64         
65         if(c=='
')
66             return 1;
67         
68         if(c==' ')
69             return PAGELEN;
70     }
71 }