UNIX系统文件与设备操作指南
1. 文件权限与属性操作
在UNIX系统中，对文件的操作涉及多个方面，其中文件权限和属性的设置尤为重要。以下是一段用于处理文件权限并打印文件信息的代码：
*perms = NULL; for (i=2; i >= 0; i--) { /* * Since we're subscripting, we don't * need the constants. Just get a * value between 0 and 7. */ j = (sbuf.st_mode >> (i*3)) & 07; /* * Get the perm bits. */ strcat(perms, modes[j]); } /* * Handle special bits which replace the 'x' * in places. */ if ((sbuf.st_mode & S_ISUID) != 0) perms[2] = 's'; if ((sbuf.st_mode & S_ISGID) != 0) perms[5] = 's'; if ((sbuf.st_mode & S_ISVTX) != 0) perms[8] = 't'; /* * Print permissions, number of links, * user and group ids. */ printf("%s%3
