Subversion Repositories planix.SVN

#include <u.h>
#include <libc.h>

int wrrd;

void
usage(void)
{
        fprint(2, "usage: rdwr [-w] file\n");
        exits("usage");
}

void
main(int argc, char **argv)
{
        int fd;
        char buf[8192];
        int n;

        ARGBEGIN{
        case 'w':
                wrrd = 1;
                break;
        default:
                usage();
        }ARGEND;

        if(argc != 1)
                usage();

        if((fd = open(argv[0], ORDWR)) < 0)
                sysfatal("open: %r");

        if(wrrd){
                n = read(fd, buf, sizeof buf);
                if(n < 0)
                        fprint(2, "read error: %r\n");
                else{
                        write(1, buf, n);
                        print("\n");
                }
        }

        while(print("> "), (n = read(0, buf, 1000)) > 0) {
                seek(fd, 0, 0);
                if(write(fd, buf, n-1) != n-1)  /* n-1: no newline */
                        fprint(2, "write error: %r\n");
                seek(fd, 0, 0);
                n = read(fd, buf, sizeof buf);
                if(n < 0)
                        fprint(2, "read error: %r\n");
                else{
                        write(1, buf, n);
                        print("\n");
                }
        }
}