48 lines
650 B
C
48 lines
650 B
C
#include <fcntl.h>
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#include <stdio.h>
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#include <stdlib.h>
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#include <unistd.h>
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#include <assert.h>
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#include <sys/wait.h>
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int main(int argc, char *argv[])
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{
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pid_t p;
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int t[2];
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assert(pipe(t) == 0);
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p = fork();
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if (p == 0){
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close(t[0]);
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dup2(t[1],STDOUT_FILENO);
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close(t[1]);
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execlp("ls","ls",NULL);
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assert(0);
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}
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p = fork();
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if (p == 0){
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int fd = open("output.txt",O_WRONLY|O_CREAT|O_APPEND,0644);
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assert(fd != -1);
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close(t[1]);
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dup2(t[0],STDIN_FILENO);
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close(t[0]);
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dup2(fd,STDOUT_FILENO);
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close(fd);
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execlp("wc","wc",NULL);
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assert(0);
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}
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close(t[0]);
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close(t[1]);
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wait(NULL);
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wait(NULL);
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return 0;
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}
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