can someone it asap

the code is

/* * usage: ./a.out input_file text_pattern * Executes the command "cat input_file | grep text_pattern | cut -b 1-10". * Note only minimal error checking is done for simplicity/shortness of code. */

#include #include #include #include #include

int main(int argc, char **argv) { int status; int i;

if (argc == 3) { // arguments for commands char *cat_args[] = {"cat", argv[1], NULL}; char *grep_args[] = {"grep", argv[2], NULL}; char *cut_args[] = {"cut", "-b", "1-10", NULL};

// file descriptors for 2 pipes: fd1 for cat-to-grep, fd2 for grep-to-cut int fd1[2], fd2[2];

// make pipe for cat to grep // fd1[0] = read end of cat->grep pipe (read by grep) // fd1[1] = write end of cat->grep pipe (written by cat)

// make pipe for grep to cut // fd2[0] = read end of grep->cut pipe (read by cut) // fd2[1] = write end of grep->cut pipe (written by grep) // fork the first child (to execute cat) if (fork() == 0) { // duplicate write end of cat->grep pipe to stdout

// close both ends of all created fd# pipes (very important!)

execvp(*cat_args, cat_args); } else // parent (assume no error) { // fork second child (to execute grep) if (fork() == 0) { // duplicate read end of cat->grep pipe to stdin (of grep)

// duplicate write end of grep->cut pipe to stdout (of grep)

// close both ends of all created fd# pipes (very important!)

execvp(*grep_args, grep_args); } else // parent (assume no error) { // fork third child (to execute cut) if (fork() == 0) { // duplicate read end of grep->cut pipe to stadin (of cut)

// close both ends of all created fd# pipes (very important!)

execvp(*cut_args, cut_args); } } } // only the parent gets here, close all pipes and wait for 3 children to finish close(fd1[0]); close(fd1[1]); close(fd2[0]); close(fd2[1]);

for (i = 0; i

return 0; }

close(fd1[0]);

close(fd1[1]);

close(fd2[0]);

close(fd2[1]);

for (i = 0; i