实现了命令more的基本功能，但还有如下缺陷：more的反白先是不能固定，不能显示百分比，在输入命令后必需按回车。
下面是代码，在FC4上使用gcc 编译通过。
1 #include <stdio.h>
2 #include <stdlib.h>
3
4 #define PAGELEN 24
5 #define LINELEN 512
6
7 void do_more(FILE *);
8 int see_more();
9 int see_more(FILE *);
10
11
12 int main(int ac, char *av[])
13 {
14 FILE *fp;
15
16 if (ac == 1)
17 do_more(stdin);
18 else
19 while(--ac)
20 if((fp = fopen(* ++av, "r")) != NULL)
21 {
22 do_more(fp);
23 fclose(fp);
24 }
25 else
26 exit(1);
27
28 return 0;
29 }
30
31 void do_more(FILE *fp)
32 /*
33 * read PAGELEN lines, then call see_more() for further instructions
34 */
35 {
36 char line[LINELEN];
37 int num_of_lines = 0;
38 int see_more(FILE *), reply;
39
40
41 // get input from stardard input device
42 /*
43 FILE *fp_tty;
44 fp_tty = fopen("/dev/tty", "r");
45 if (fp_tty = NULL)
46 exit(1);*/
47
48 FILE *fp_tty;
49
50 fp_tty = fopen( "/dev/tty", "r" );
51 if ( fp_tty == NULL )
52 exit(1);
53
54 while (fgets(line, LINELEN, fp))
55 {
56 if ( num_of_lines == PAGELEN)
57 {
58 //printf("\n====== \n");
59 //reply = see_more();
60 reply = see_more(fp_tty);
61 if (reply == 0) break;
62 num_of_lines -= reply;
63 }
64
65 if (fputs(line, stdout) == EOF)
66 exit(1);
67
68 num_of_lines++;
69
70 //printf("\n====== num_of_lines = %d \n", num_of_lines);
71 }
72 }
73
74 int see_more()
75 /*
76 * print message , wait for response, return # of lines to advance
77 * q means no, space means yes, CR means one line.
78 */
79 {
80 int c;
81 printf("\033[7m more? \033[m");
82 while ( (c = getchar()) != EOF)
83 {
84 if ( c == 'q') return 0;
85 if ( c == ' ') return PAGELEN;
86 if ( c == '\n') return 1;
87 }
88
89 return 0;
90 }
91
92 int see_more(FILE *cmd)
93 {
94 int c;
95 printf("\033[7m more? \033[m");
96 while ( (c = getc(cmd)) != EOF)
97 {
98 if ( c == 'q') return 0;
99 if ( c == ' ') return PAGELEN;
100 if ( c == '\n') return 1;
101 }
102
103 return 0;
104 }
105
有两个子函数，do_more()和see_more()，前者处理显示，后者处理命令。
以后在进行改进。