42 lines
636 B
C
42 lines
636 B
C
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#include <stdio.h>
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#include <unistd.h>
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#include <stdlib.h>
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#include <assert.h>
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#include <sys/wait.h>
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#include <fcntl.h>
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int main(int argc, char *argv[])
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{
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pid_t p1,p2;
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int fd[2];
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assert(pipe(fd) == 0);
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p1 = fork();
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if (p1 == 0){
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close(fd[0]);
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dup2(fd[1],STDOUT_FILENO);
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close(fd[1]);
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execlp("ls","ls",NULL);
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assert(0);
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}
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p2 = fork();
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if (p2 == 0){
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int out = open("output.txt",O_CREAT|O_WRONLY|O_APPEND,0644);
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dup2(out,STDOUT_FILENO);
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close(out);
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close(fd[1]);
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dup2(fd[0],STDIN_FILENO);
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close(fd[0]);
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execlp("wc","wc",NULL);
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assert(0);
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}
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close(fd[0]);
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close(fd[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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