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copied!<p>You don't need to pass the <code>end</code> argument, instead increment the pointer to your command array. You are passing the initial array to the execvp call so it tries to execute <code>ls</code> multiple times. Further, you need a break statement after setting the <code>listaCommand[cont]</code> to <code>NULL</code> because after the iteration <code>cont</code> is incremented. Also I think you need to protect the <code>execvp</code> call so that the parent does not call it after the processing is done. </p> <pre><code>#include <stdio.h> #include <string.h> #include <unistd.h> #include <stdlib.h> #include <sys/wait.h> #define fatal() exit(1) void pipes (char *listaCommand[], char **argv) { printf("pipes %s\n", listaCommand[0]); int cont = 0; for (;listaCommand[cont]; cont++) { if (listaCommand[cont][0] == '|'){ int pid2, status; int pipefd[2], ret; listaCommand[cont] = NULL; ret = pipe (pipefd); if (ret < 0) fatal(); /* Now fork. */ pid2 = fork (); if (pid2 <0) fatal (); if (pid2 > 0) { printf ("P: waiting for child\n"); wait (&status); close(STDIN_FILENO); dup(pipefd[0]); close(pipefd[0]); close(pipefd[1]); /*execvp (auxCommand[0], auxCommand);*/ pipes(listaCommand + cont + 1, argv); /*break;*/ } else { close (STDOUT_FILENO); dup (pipefd[1]); close (pipefd[1]); close (pipefd[0]); break; } } } if (listaCommand[0]) { execvp (listaCommand[0], listaCommand); printf ("%s: command not found.\n", listaCommand[0]); /* Exec failed. */ exit(EXIT_FAILURE); } } int main() { char *args[] = { "ls", "-al", "|", "sort", "|" , "tr", "[a-z]", "[A-Z]", 0 }; pipes(args, 0); return 0; } </code></pre>

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