diff --git a/apps/cat.cpp b/apps/cat.cpp
index ee506ddc..e4799b5c 100644
--- a/apps/cat.cpp
+++ b/apps/cat.cpp
@@ -31,7 +31,7 @@ static void do_cat(StringView path)
     if (f != stdin) fclose(f);
 }
 
-int main(int argc, char** argv)
+Result<int> luna_main(int argc, char** argv)
 {
     StringView filename;
 
@@ -42,4 +42,6 @@ int main(int argc, char** argv)
     do_cat(filename);
 
     for (auto file : extra_files) { do_cat(file); }
+
+    return 0;
 }
diff --git a/apps/edit.cpp b/apps/edit.cpp
index 0871047f..5c7ff17a 100644
--- a/apps/edit.cpp
+++ b/apps/edit.cpp
@@ -5,7 +5,7 @@
 #include <stdlib.h>
 #include <string.h>
 
-int main(int argc, char** argv)
+Result<int> luna_main(int argc, char** argv)
 {
     StringView pathname;
 
@@ -13,7 +13,7 @@ int main(int argc, char** argv)
     parser.add_positional_argument(pathname, "path"_sv, true);
     parser.parse(argc, argv);
 
-    auto file = os::File::open_or_create(pathname, os::File::WriteOnly).release_value();
+    auto file = TRY(os::File::open_or_create(pathname, os::File::WriteOnly));
 
     char buffer[4096];
 
@@ -21,7 +21,7 @@ int main(int argc, char** argv)
     {
         char* rc = fgets(buffer, sizeof(buffer), stdin);
         if (rc == 0) break;
-        file->write(StringView { buffer });
+        TRY(file->write(StringView { buffer }));
     }
 
     return 0;
diff --git a/apps/ls.cpp b/apps/ls.cpp
index 72facc9d..2b848022 100644
--- a/apps/ls.cpp
+++ b/apps/ls.cpp
@@ -5,7 +5,7 @@
 #include <stdio.h>
 #include <unistd.h>
 
-int main(int argc, char** argv)
+Result<int> luna_main(int argc, char** argv)
 {
     StringView pathname;
     bool show_all { false };
diff --git a/apps/rm.cpp b/apps/rm.cpp
index 2fb33283..c122cbbe 100644
--- a/apps/rm.cpp
+++ b/apps/rm.cpp
@@ -1,7 +1,7 @@
 #include <os/ArgumentParser.h>
 #include <stdio.h>
 
-int main(int argc, char** argv)
+Result<int> luna_main(int argc, char** argv)
 {
     StringView path;
 
@@ -14,4 +14,6 @@ int main(int argc, char** argv)
         perror("rm");
         return 1;
     }
+
+    return 0;
 }
diff --git a/apps/sh.cpp b/apps/sh.cpp
index 09fcf06c..f3043d98 100644
--- a/apps/sh.cpp
+++ b/apps/sh.cpp
@@ -47,7 +47,7 @@ static Result<Vector<char*>> split_command_into_argv(const char* cmd)
     exit(1);
 }
 
-int main(int argc, char** argv)
+Result<int> luna_main(int argc, char** argv)
 {
     StringView file;
     StringView command;
diff --git a/apps/su.cpp b/apps/su.cpp
index 8f518801..f699dc0e 100644
--- a/apps/su.cpp
+++ b/apps/su.cpp
@@ -51,7 +51,7 @@ char* getpass()
     return buf;
 }
 
-int main(int argc, char** argv)
+Result<int> luna_main(int argc, char** argv)
 {
     StringView name;
 
@@ -92,4 +92,6 @@ int main(int argc, char** argv)
     chdir(entry->pw_dir);
 
     execl(entry->pw_shell, entry->pw_shell, NULL);
+
+    return 1;
 }
diff --git a/libos/CMakeLists.txt b/libos/CMakeLists.txt
index 00d2f22a..504de652 100644
--- a/libos/CMakeLists.txt
+++ b/libos/CMakeLists.txt
@@ -6,6 +6,7 @@ set(SOURCES
     ${HEADERS}
     src/ArgumentParser.cpp
     src/File.cpp
+    src/Main.cpp
 )
 
 add_library(os ${SOURCES})
diff --git a/libos/include/os/Main.h b/libos/include/os/Main.h
new file mode 100644
index 00000000..a53f9941
--- /dev/null
+++ b/libos/include/os/Main.h
@@ -0,0 +1,4 @@
+#pragma once
+#include <luna/Result.h>
+
+Result<int> luna_main(int argc, char** argv);
diff --git a/libos/src/Main.cpp b/libos/src/Main.cpp
new file mode 100644
index 00000000..c14548ed
--- /dev/null
+++ b/libos/src/Main.cpp
@@ -0,0 +1,23 @@
+#include <os/Main.h>
+
+#include <errno.h>
+#include <stdio.h>
+
+int g_argc;
+char** g_argv;
+
+__attribute__((weak)) int main(int argc, char** argv)
+{
+    g_argc = argc;
+    g_argv = argv;
+
+    int result;
+    bool ok = luna_main(argc, argv).try_set_value_or_error(result, errno);
+    if (!ok)
+    {
+        perror(g_argv[0]);
+        return 1;
+    }
+
+    return result;
+}