diff --git a/README.md b/README.md
index aa3f1ea..0cb51ba 100644
--- a/README.md
+++ b/README.md
@@ -15,3 +15,17 @@ _
          |
         _
 ```
+
+## To-Do
+
+1. Pipes
+2. Exclude things inside quote marks from string splitting and substitutions
+3. Interrupts ^C and ^Z, bg, fg
+    - & and &&, ;
+4. Wildcard substitutions *, ? etc
+5. tab completion, handling escape sequences like ^[[D
+6. Functions and variables
+7. PS1
+
+
+
diff --git a/main.c b/main.c
index a2e75fa..25a30e9 100644
--- a/main.c
+++ b/main.c
@@ -9,6 +9,9 @@ int get_alias(Alias *alias, State *state, char *name);
 int add_alias(State* state, char *name, char *substitution); 
 int del_alias(State *state, char *name); 
 int repl(State* state, FILE *input); 
+int run_command(State *state, int argc, char *argv[]); 
+int get_array_element(ArrayElement **ret, GrowingArray* array, char* key); 
+int del_array_element(GrowingArray* array, char* key); 
 
 GrowingArray get_growing_array(size_t num_elements, size_t size_elem) {
     GrowingArray arr;
@@ -199,14 +202,83 @@ void shutdown(State *state) {
     exit(0);
 }
 
+int check_pipes(State* state, int num_args, char* args[]) {
+
+    int left = 0;
+    int num_commands = 0;
+    int space = 10;
+    // an array of string-arrays which end in NULL
+    char** *pipes = calloc(space, sizeof(char***)); 
+
+    for (int i = 0; i < num_args; i++) {
+        if (!strcmp(args[i], "|") || i == num_args - 1) {
+            int command_length = i - left + 1 + num_commands;
+            char **command = calloc(command_length, sizeof(char**));
+            // copy the command into the array
+            for (int k = 0; k < command_length - 1; k++) {
+                command[k] = args[left + k];
+            }
+            command[command_length - 1] = 0;
+
+            // grow the array if needed
+            if (num_commands == space - 2) {
+                pipes = calloc((space *= 2), sizeof(char***));
+            }
+
+            pipes[num_commands] = command;
+            num_commands++;
+
+            left = i + 1;
+        }
+    }
+
+    if (num_commands == 1) {
+        return ER_NOT_EXISTS;
+    }
+
+    int pipein[2];
+    int pipeout[2];
+    memset(pipein, 0, sizeof(int) * 2);
+    memset(pipeout, 0, sizeof(int) * 2);
+
+    pipe(pipein);
+    pipe(pipeout);
+    // 0 is read, 1 is write
+
+    pid_t child;
+
+    int in;
+    int out;
+
+    in = 0;
+    out = pipeout[1];
+
+    for (int i = 0; i < num_commands; i++) {
+        execute(in, out, pipes[i], &child);
+        if (i != num_commands - 1) {
+            if (in == pipein[0]) {
+                in = pipeout[0];
+                out = pipein[1];
+            } else {
+                in = pipein[0];
+                out = pipeout[1];
+            }
+        } else {
+            out = 1; 
+            in = out - 1;
+        }
+    }
+
+    return ER_SUCCESS;
+}
+
 int check_builtins(State *state, int num_args, char *args[]) {
     char *builtins[NUM_BUILTINS] = {
         "cd",
         "alias",
         "unalias"
     };
-    
-     if (!strcmp(args[0], "cd")) {
+    if (!strcmp(args[0], "cd")) {
          if (num_args == 1) {
              chdir(getenv("HOME"));
              return ER_SUCCESS;
@@ -343,15 +415,12 @@ int check_aliases(State *state, char **substitution, char *name) {
     return ER_FAILURE;
 }
 
-
-int run_command(State *state, int argc, char *argv[]) {
-    pid_t child;
-
+int expand_command(State *state, int argc, char* argv[]) {
     if (argc == 0) {
         return ER_FAILURE;
     }
-    char *substitution;
 
+    char *substitution;
     if (!check_aliases(state, &substitution, argv[0])) {
         strip_char(argv[0], ' ');
         argv[0] = reallocarray(argv[0], strlen(substitution) + 1, sizeof(char));
@@ -362,25 +431,29 @@ int run_command(State *state, int argc, char *argv[]) {
         join_string(&joined, argc, argv, " ");
         split_string(&new_argv, &len, joined, ' ');
 
-        //run_command(state, len, new_argv);
-        execute(stdin, stdout, new_argv, &child);
-        waitpid(child, NULL, 0);
-        return ER_SUCCESS;
+        run_command(state, len, new_argv);
 
        for (int i = 0 ; i < len; i ++) {
             free(new_argv[i]);
         }
         free(new_argv);
+        return ER_SUCCESS;
+    } else {
+        run_command(state, argc, argv);
     }
+    return ER_SUCCESS;
+}
 
+int run_command(State *state, int argc, char *argv[]) {
+    pid_t child;
     if (check_builtins(state, argc, argv) == ER_NOT_EXISTS) {
-        execute(stdin, stdout, argv, &child);
+        execute(0,1, argv, &child);
         waitpid(child, NULL, 0);
     }
-
     return ER_SUCCESS;
 }
 
+/* read eval print loop until EOF */
 int repl(State* state, FILE *input) {
     while (true) {
         char *line;
@@ -398,7 +471,11 @@ int repl(State* state, FILE *input) {
 
         split_string(&sep_string, &num_words, line, ' ');
 
-        run_command(state, num_words, sep_string);
+        int err = check_pipes(state, num_words, sep_string);
+        if (err == ER_NOT_EXISTS) {
+            expand_command(state, num_words, sep_string);
+        }
+
 
         for (int i = 0; i < num_words; i++) {
             free(sep_string[i]);
diff --git a/run.c b/run.c
index c27e7f4..233aa78 100644
--- a/run.c
+++ b/run.c
@@ -5,9 +5,7 @@
  *
  * Returns true on success or 1 on failure.
  */
-int execute(FILE *in, FILE *out, char *args[], pid_t* child_ID) {
-    int in_FD = fileno(in);
-    int out_FD = fileno(out);
+int execute(int in_FD, int out_FD, char *args[], pid_t* child_ID) {
 
     int err = fork();
 
diff --git a/run.h b/run.h
index 0adca76..5e82151 100644
--- a/run.h
+++ b/run.h
@@ -8,7 +8,7 @@
 #ifndef RUNH
 #define RUNH
 
-int execute(FILE *in, FILE *out, char *args[], pid_t* child_ID); 
+int execute(int in_FD, int out_FD, char *args[], pid_t* child_ID); 
 
 int change_dir(char *dir);