58 lines
811 B
C
58 lines
811 B
C
#include <u.h>
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#include <libc.h>
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int wrrd;
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void
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usage(void)
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{
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fprint(2, "usage: rdwr [-w] file\n");
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exits("usage");
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}
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void
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main(int argc, char **argv)
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{
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int fd;
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char buf[8192];
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int n;
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ARGBEGIN{
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case 'w':
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wrrd = 1;
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break;
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default:
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usage();
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}ARGEND;
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if(argc != 1)
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usage();
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if((fd = open(argv[0], ORDWR)) < 0)
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sysfatal("open: %r");
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if(wrrd){
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n = read(fd, buf, sizeof buf);
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if(n < 0)
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fprint(2, "read error: %r\n");
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else{
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write(1, buf, n);
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print("\n");
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}
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}
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while(print("> "), (n = read(0, buf, 1000)) > 0) {
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seek(fd, 0, 0);
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if(write(fd, buf, n-1) != n-1) /* n-1: no newline */
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fprint(2, "write error: %r\n");
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seek(fd, 0, 0);
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n = read(fd, buf, sizeof buf);
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if(n < 0)
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fprint(2, "read error: %r\n");
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else{
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write(1, buf, n);
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print("\n");
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}
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}
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}
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