diff --git a/AK/Vector.h b/AK/Vector.h
index 330d33cd0d2..10b7ee5dcdd 100644
--- a/AK/Vector.h
+++ b/AK/Vector.h
@@ -116,6 +116,21 @@ public:
         m_impl->remove(index);
     }
 
+    void append(Vector<T>&& other)
+    {
+        Vector<T> tmp = move(other);
+        ensureCapacity(size() + tmp.size());
+        for (auto&& v : tmp) {
+            uncheckedAppend(move(v));
+        }
+    }
+
+    void uncheckedAppend(T&& value)
+    {
+        new (m_impl->slot(m_impl->m_size)) T(move(value));
+        ++m_impl->m_size;
+    }
+
     void append(T&& value)
     {
         ensureCapacity(size() + 1);
diff --git a/Kernel/MemoryManager.cpp b/Kernel/MemoryManager.cpp
index 0f32eb96795..c22e8b3e0e4 100644
--- a/Kernel/MemoryManager.cpp
+++ b/Kernel/MemoryManager.cpp
@@ -34,9 +34,7 @@ void MemoryManager::initializePaging()
     memset(m_pageTableOne, 0, 4096);
     memset(m_pageDirectory, 0, 4096);
 
-    kprintf("MM: Page directory @ %p\n", m_pageDirectory);
-    kprintf("MM: Page table zero @ %p\n", m_pageTableZero);
-    kprintf("MM: Page table one @ %p\n", m_pageTableOne);
+    kprintf("[MM] Page directory @ %p\n", m_pageDirectory);
 
     // Make null dereferences crash.
     protectMap(LinearAddress(0), 4 * KB);
@@ -72,7 +70,7 @@ auto MemoryManager::ensurePTE(LinearAddress linearAddress) -> PageTableEntry
 
     PageDirectoryEntry pde = PageDirectoryEntry(&m_pageDirectory[pageDirectoryIndex]);
     if (!pde.isPresent()) {
-        kprintf("PDE %u !present, allocating\n", pageDirectoryIndex);
+        kprintf("[MM] PDE %u not present, allocating\n", pageDirectoryIndex);
         if (pageDirectoryIndex == 0) {
             pde.setPageTableBase((dword)m_pageTableZero);
             pde.setUserAllowed(true);
@@ -85,7 +83,7 @@ auto MemoryManager::ensurePTE(LinearAddress linearAddress) -> PageTableEntry
             pde.setWritable(true);
         } else {
             auto* pageTable = allocatePageTable();
-            kprintf("allocated page table %u (for laddr=%p) at %p\n", pageDirectoryIndex, linearAddress.get(), pageTable);
+            kprintf("[MM] Allocated page table #%u (for laddr=%p) at %p\n", pageDirectoryIndex, linearAddress.get(), pageTable);
             memset(pageTable, 0, 4096);
             pde.setPageTableBase((dword)pageTable);
             pde.setUserAllowed(true);
@@ -134,7 +132,7 @@ void MemoryManager::initialize()
 PageFaultResponse MemoryManager::handlePageFault(const PageFault& fault)
 {
     ASSERT_INTERRUPTS_DISABLED();
-    kprintf("MM: handlePageFault(%w) at laddr=%p\n", fault.code(), fault.address().get());
+    kprintf("[MM] handlePageFault(%w) at laddr=%p\n", fault.code(), fault.address().get());
     if (fault.isNotPresent()) { 
         kprintf("  >> NP fault!\n");
     } else if (fault.isProtectionViolation()) {
@@ -143,11 +141,36 @@ PageFaultResponse MemoryManager::handlePageFault(const PageFault& fault)
     return PageFaultResponse::ShouldCrash;
 }
 
+void MemoryManager::registerZone(Zone& zone)
+{
+    ASSERT_INTERRUPTS_DISABLED();
+    m_zones.set(&zone);
+}
+
+void MemoryManager::unregisterZone(Zone& zone)
+{
+    ASSERT_INTERRUPTS_DISABLED();
+    m_zones.remove(&zone);
+    m_freePages.append(move(zone.m_pages));
+}
+
+Zone::Zone(Vector<PhysicalAddress>&& pages)
+    : m_pages(move(pages))
+{
+    MM.registerZone(*this);
+}
+
+Zone::~Zone()
+{
+    MM.unregisterZone(*this);
+}
+
 RetainPtr<Zone> MemoryManager::createZone(size_t size)
 {
+    InterruptDisabler disabler;
     auto pages = allocatePhysicalPages(ceilDiv(size, PAGE_SIZE));
     if (pages.isEmpty()) {
-        kprintf("MM: createZone: no physical pages for size %u", size);
+        kprintf("[MM] createZone: no physical pages for size %u", size);
         return nullptr;
     }
     return adopt(*new Zone(move(pages)));
@@ -170,7 +193,7 @@ byte* MemoryManager::quickMapOnePage(PhysicalAddress physicalAddress)
 {
     ASSERT_INTERRUPTS_DISABLED();
     auto pte = ensurePTE(LinearAddress(4 * MB));
-    kprintf("quickmap %x @ %x {pte @ %p}\n", physicalAddress.get(), 4*MB, pte.ptr());
+    kprintf("[MM] quickmap %x @ %x {pte @ %p}\n", physicalAddress.get(), 4*MB, pte.ptr());
     pte.setPhysicalPageBase(physicalAddress.pageBase());
     pte.setPresent(true);
     pte.setWritable(true);
@@ -297,7 +320,7 @@ bool MemoryManager::mapRegionsForTask(Task& task)
 bool copyToZone(Zone& zone, const void* data, size_t size)
 {
     if (zone.size() < size) {
-        kprintf("copyToZone: can't fit %u bytes into zone with size %u\n", size, zone.size());
+        kprintf("[MM] copyToZone: can't fit %u bytes into zone with size %u\n", size, zone.size());
         return false;
     }
 
@@ -314,4 +337,3 @@ bool copyToZone(Zone& zone, const void* data, size_t size)
 
     return true;
 }
-
diff --git a/Kernel/MemoryManager.h b/Kernel/MemoryManager.h
index 0c886074334..4ed3ff66f7a 100644
--- a/Kernel/MemoryManager.h
+++ b/Kernel/MemoryManager.h
@@ -5,7 +5,7 @@
 #include <AK/Retainable.h>
 #include <AK/RetainPtr.h>
 #include <AK/Vector.h>
-#include <AK/HashMap.h>
+#include <AK/HashTable.h>
 #include "Task.h"
 
 class Task;
@@ -17,7 +17,7 @@ enum class PageFaultResponse {
 
 struct Zone : public Retainable<Zone> {
 public:
-    ~Zone() { }
+    ~Zone();
     size_t size() const { return m_pages.size() * PAGE_SIZE; }
 
     const Vector<PhysicalAddress>& pages() const { return m_pages; }
@@ -25,10 +25,7 @@ public:
 private:
     friend class MemoryManager;
     friend bool copyToZone(Zone&, const void* data, size_t);
-    explicit Zone(Vector<PhysicalAddress>&& pages)
-        : m_pages(move(pages))
-    {
-    }
+    explicit Zone(Vector<PhysicalAddress>&&);
 
     Vector<PhysicalAddress> m_pages;
 };
@@ -38,6 +35,7 @@ bool copyToZone(Zone&, const void* data, size_t);
 #define MM MemoryManager::the()
 
 class MemoryManager {
+    friend ByteBuffer procfs$mm();
 public:
     static MemoryManager& the() PURE;
 
@@ -62,6 +60,9 @@ public:
     bool mapRegionsForTask(Task&);
     bool unmapRegionsForTask(Task&);
 
+    void registerZone(Zone&);
+    void unregisterZone(Zone&);
+
 private:
     MemoryManager();
     ~MemoryManager();
@@ -161,7 +162,7 @@ private:
     dword* m_pageTableZero;
     dword* m_pageTableOne;
 
-    HashMap<int, RetainPtr<Zone>> m_zones;
+    HashTable<Zone*> m_zones;
 
     Vector<PhysicalAddress> m_freePages;
 };
diff --git a/Kernel/ProcFileSystem.cpp b/Kernel/ProcFileSystem.cpp
index 8457361cf4c..f7b7f3f5cbc 100644
--- a/Kernel/ProcFileSystem.cpp
+++ b/Kernel/ProcFileSystem.cpp
@@ -118,6 +118,18 @@ void ProcFileSystem::removeProcess(Task& task)
     m_pid2inode.remove(pid);
 }
 
+ByteBuffer procfs$mm()
+{
+    InterruptDisabler disabler;
+    auto buffer = ByteBuffer::createUninitialized(1024);
+    char* ptr = (char*)buffer.pointer();
+    ptr += ksprintf(ptr, "Zone count: %u\n", MM.m_zones.size());
+    ptr += ksprintf(ptr, "Free physical pages: %u\n", MM.m_freePages.size());
+    buffer.trim(ptr - (char*)buffer.pointer());
+    return buffer;
+}
+
+
 ByteBuffer procfs$mounts()
 {
     InterruptDisabler disabler;
@@ -171,6 +183,7 @@ ByteBuffer procfs$summary()
 bool ProcFileSystem::initialize()
 {
     SyntheticFileSystem::initialize();
+    addFile(createGeneratedFile("mm", procfs$mm));
     addFile(createGeneratedFile("mounts", procfs$mounts));
     addFile(createGeneratedFile("kmalloc", procfs$kmalloc));
     addFile(createGeneratedFile("summary", procfs$summary));
diff --git a/Kernel/sync-sh b/Kernel/sync-sh
index 8584eaa626a..4847c68a401 100755
--- a/Kernel/sync-sh
+++ b/Kernel/sync-sh
@@ -15,6 +15,7 @@ cp ../Userland/cat mnt/bin/cat
 cp ../Userland/uname mnt/bin/uname
 cp ../Userland/clear mnt/bin/clear
 cp ../Userland/tst mnt/bin/tst
+cp ../Userland/mm mnt/bin/mm
 cp kernel.map mnt/
 umount mnt
 sync
diff --git a/Userland/.gitignore b/Userland/.gitignore
index e365fd391b0..f6b0db76150 100644
--- a/Userland/.gitignore
+++ b/Userland/.gitignore
@@ -13,3 +13,4 @@ cat
 uname
 clear
 tst
+mm
diff --git a/Userland/Makefile b/Userland/Makefile
index 72057879704..bc8e0ecaee3 100644
--- a/Userland/Makefile
+++ b/Userland/Makefile
@@ -12,7 +12,8 @@ OBJS = \
        cat.o \
        uname.o \
        clear.o \
-       tst.o
+       tst.o \
+       mm.o
 
 APPS = \
        id \
@@ -28,7 +29,8 @@ APPS = \
        cat \
        uname \
        clear \
-       tst
+       tst \
+       mm
 
 ARCH_FLAGS =
 STANDARD_FLAGS = -std=c++17 -nostdinc++ -nostdlib
@@ -90,6 +92,9 @@ clear: clear.o
 tst: tst.o
 	$(LD) -o $@ $(LDFLAGS) $< ../LibC/LibC.a
 
+mm: mm.o
+	$(LD) -o $@ $(LDFLAGS) $< ../LibC/LibC.a
+
 .cpp.o:
 	@echo "CXX $<"; $(CXX) $(CXXFLAGS) -o $@ -c $<
 
diff --git a/Userland/mm.cpp b/Userland/mm.cpp
new file mode 100644
index 00000000000..ee035988677
--- /dev/null
+++ b/Userland/mm.cpp
@@ -0,0 +1,25 @@
+#include <LibC/stdio.h>
+#include <LibC/unistd.h>
+
+int main(int c, char** v)
+{
+    int fd = open("/proc/mm");
+    if (fd == -1) {
+        perror("failed to open /proc/mm");
+        return 1;
+    }
+    for (;;) {
+        char buf[128];
+        ssize_t nread = read(fd, buf, sizeof(buf));
+        if (nread == 0)
+            break;
+        if (nread < 0) {
+            perror("failed to read");
+            return 2;
+        }
+        for (ssize_t i = 0; i < nread; ++i) {
+            putchar(buf[i]);
+        }
+    }
+    return 0;
+}
diff --git a/Userland/ps.cpp b/Userland/ps.cpp
index a1cc620c208..ec49c480d0e 100644
--- a/Userland/ps.cpp
+++ b/Userland/ps.cpp
@@ -5,7 +5,7 @@ int main(int c, char** v)
 {
     int fd = open("/proc/summary");
     if (fd == -1) {
-        printf("failed to open /proc/summary :(\n");
+        perror("failed to open /proc/summary");
         return 1;
     }
     for (;;) {
@@ -14,7 +14,7 @@ int main(int c, char** v)
         if (nread == 0)
             break;
         if (nread < 0) {
-            printf("failed to read :(\n");
+            perror("failed to read");
             return 2;
         }
         for (ssize_t i = 0; i < nread; ++i) {
diff --git a/Userland/sh.cpp b/Userland/sh.cpp
index b172f6fa9c9..3f503419a63 100644
--- a/Userland/sh.cpp
+++ b/Userland/sh.cpp
@@ -26,6 +26,13 @@ static int sh_pwd(int, const char**)
     return 0;
 }
 
+static int sh_exit(int, const char**)
+{
+    printf("Good-bye!\n");
+    exit(0);
+    return 0;
+}
+
 static int sh_cd(int argc, const char** argv)
 {
     if (argc == 1) {
@@ -77,6 +84,10 @@ static bool handle_builtin(int argc, const char** argv, int& retval)
         retval = sh_pwd(argc, argv);
         return true;
     }
+    if (!strcmp(argv[0], "exit")) {
+        retval = sh_exit(argc, argv);
+        return true;
+    }
     return false;
 }