diff --git a/apps/base64.cpp b/apps/base64.cpp
index 8bcf2db2..24cc32e4 100644
--- a/apps/base64.cpp
+++ b/apps/base64.cpp
@@ -18,16 +18,13 @@ Result<int> luna_main(int argc, char** argv)
 
     auto file = TRY(os::File::open_input_file(path));
 
-    auto output = os::File::standard_output();
-
     if (!decode)
     {
         auto data = TRY(file->read_all());
 
         auto encoded = TRY(Base64::encode(data));
 
-        output->write(encoded.view());
-        output->write("\n"_sv);
+        os::println("%s", encoded.chars());
     }
     else
     {
@@ -35,7 +32,7 @@ Result<int> luna_main(int argc, char** argv)
 
         auto decoded = TRY(Base64::decode(data.view(), allow_garbage));
 
-        output->write(decoded);
+        os::File::standard_output()->write(decoded);
     }
 
     return 0;
diff --git a/apps/date.cpp b/apps/date.cpp
index 945203a8..17bde216 100644
--- a/apps/date.cpp
+++ b/apps/date.cpp
@@ -1,11 +1,11 @@
 #include <os/ArgumentParser.h>
+#include <os/File.h>
 
 #include <stddef.h>
-#include <stdio.h>
 #include <stdlib.h>
 #include <time.h>
 
-int main(int argc, char** argv)
+Result<int> luna_main(int argc, char** argv)
 {
     StringView date;
 
@@ -20,5 +20,7 @@ int main(int argc, char** argv)
     if (date.is_empty()) { now = time(NULL); }
     else { now = strtol(date.chars(), nullptr, 10); }
 
-    fputs(ctime(&now), stdout);
+    os::print("%s", ctime(&now));
+
+    return 0;
 }
diff --git a/apps/ls.cpp b/apps/ls.cpp
index 7955101f..3ea716d9 100644
--- a/apps/ls.cpp
+++ b/apps/ls.cpp
@@ -1,8 +1,6 @@
 #include <os/ArgumentParser.h>
 #include <os/Directory.h>
-
-#include <stdio.h>
-#include <unistd.h>
+#include <os/File.h>
 
 Result<int> luna_main(int argc, char** argv)
 {
@@ -27,14 +25,8 @@ Result<int> luna_main(int argc, char** argv)
 
     auto files = TRY(dir->list(filter));
 
-    int first_ent = 1;
-    for (const auto& file : files)
-    {
-        printf(first_ent ? "%s" : " %s", file.chars());
-        first_ent = 0;
-    }
-
-    putchar('\n');
+    auto list = TRY(String::join(files, " "_sv));
+    os::println("%s", list.chars());
 
     return 0;
 }
diff --git a/apps/sh.cpp b/apps/sh.cpp
index 0d6bed61..f51a89fb 100644
--- a/apps/sh.cpp
+++ b/apps/sh.cpp
@@ -80,7 +80,7 @@ Result<int> luna_main(int argc, char** argv)
         if (interactive)
         {
             auto cwd = TRY(os::FileSystem::working_directory());
-            printf("%s@%s:%s%c ", username, hostname, cwd.chars(), prompt_end);
+            os::print("%s@%s:%s%c ", username, hostname, cwd.chars(), prompt_end);
         }
 
         auto cmd = TRY(input_file->read_line());
diff --git a/libos/src/ArgumentParser.cpp b/libos/src/ArgumentParser.cpp
index d13d05f6..d5e44281 100644
--- a/libos/src/ArgumentParser.cpp
+++ b/libos/src/ArgumentParser.cpp
@@ -1,5 +1,6 @@
 #include <luna/StringBuilder.h>
 #include <os/ArgumentParser.h>
+#include <os/File.h>
 #include <stdio.h>
 #include <stdlib.h>
 #include <sys/utsname.h>
@@ -165,7 +166,7 @@ namespace os
 
                     if (found) continue;
 
-                    fprintf(stderr, "%s: unrecognized option '%s'\n", program_name.chars(), arg.chars());
+                    os::eprintln("%s: unrecognized option '%s'", program_name.chars(), arg.chars());
                     short_usage(program_name);
                 }
                 else if (looks_like_short_flag(arg))
@@ -213,7 +214,7 @@ namespace os
 
                         if (found) continue;
 
-                        fprintf(stderr, "%s: invalid option -- '%c'\n", program_name.chars(), c);
+                        os::eprintln("%s: invalid option -- '%c'", program_name.chars(), c);
                         short_usage(program_name);
                     }
 
@@ -235,8 +236,8 @@ namespace os
         {
             if (current_value_argument->required)
             {
-                fprintf(stderr, "%s: option '--%s' requires an argument\n", program_name.chars(),
-                        current_value_argument->long_flag.chars());
+                os::eprintln("%s: option '--%s' requires an argument", program_name.chars(),
+                             current_value_argument->long_flag.chars());
                 short_usage(program_name);
             }
             else { *current_value_argument->out = current_value_argument->fallback; }
@@ -247,7 +248,7 @@ namespace os
         {
             if (arg.required)
             {
-                fprintf(stderr, "%s: required argument '%s' not provided\n", program_name.chars(), arg.name.chars());
+                os::eprintln("%s: required argument '%s' not provided", program_name.chars(), arg.name.chars());
                 short_usage(program_name);
             }
             else { *arg.out = arg.fallback; }
@@ -354,8 +355,8 @@ namespace os
     void ArgumentParser::short_usage(StringView program_name)
     {
         if (m_add_short_help_flag || m_add_long_help_flag)
-            fprintf(stderr, "Try running '%s %s' for more information.\n", program_name.chars(),
-                    m_add_long_help_flag ? "--help" : "-h");
+            os::eprintln("Try running '%s %s' for more information.", program_name.chars(),
+                         m_add_long_help_flag ? "--help" : "-h");
 
         exit(1);
     }