diff --git a/.gitignore b/.gitignore
index 70a8511..6ccae54 100644
--- a/.gitignore
+++ b/.gitignore
@@ -36,7 +36,9 @@ ltmain.sh
 m4/
 missing
 
-ch??ex??
+# build artifacts
+ods/src/ch??ex??
 *_test
 *.la
 *_bench
+misc/kf/kf
diff --git a/misc/kf/build.yaml b/misc/kf/build.yaml
index ab57cc6..2a3a8f5 100644
--- a/misc/kf/build.yaml
+++ b/misc/kf/build.yaml
@@ -5,5 +5,5 @@ compilers:
 targets:
   cc:
     kf:
-      - io.cc
+      - interface.cc
       - kf.cc
\ No newline at end of file
diff --git a/misc/kf/interface.cc b/misc/kf/interface.cc
new file mode 100644
index 0000000..44c9091
--- /dev/null
+++ b/misc/kf/interface.cc
@@ -0,0 +1,3 @@
+#ifdef __linux__
+#include "io-linux.cc"
+#endif
\ No newline at end of file
diff --git a/misc/kf/io-linux.cc b/misc/kf/io-linux.cc
new file mode 100644
index 0000000..34f3211
--- /dev/null
+++ b/misc/kf/io-linux.cc
@@ -0,0 +1,62 @@
+#include <iostream>
+#include "io.h"
+#include "io-linux.h"
+
+char
+Console::rdch()
+{
+	char ch;
+	std::cin >> ch;
+	return ch;
+}
+
+
+void
+Console::wrch(char c)
+{
+	std::cout << c;
+}
+
+void
+Console::rdbuf(char *buf, size_t len, bool stopat, char stopch)
+{
+	size_t	n = 0;
+	char	ch;
+
+	while (n < len) {
+		std::cin >> ch;
+		if (stopat && stopch == ch) {
+			break;
+		}
+
+		buf[n] = ch;
+	}
+}
+
+void
+Console::wrbuf(char *buf, size_t len)
+{
+	for (size_t n = 0; n < len; n++) {
+		std::cout << buf[n];
+	}
+}
+
+// Line I/O
+bool
+Console::rdln(char *buf, size_t len) {
+	size_t	n = 0;
+	char	ch;
+	bool	line = false;
+
+	while (n < len) {
+		std::cin >> ch;
+		if (ch == 0xa) {
+			line = true;
+			break;
+		}
+
+		buf[n] = ch;
+	}
+
+	return line;
+}
\ No newline at end of file
diff --git a/misc/kf/io-linux.h b/misc/kf/io-linux.h
new file mode 100644
index 0000000..087168d
--- /dev/null
+++ b/misc/kf/io-linux.h
@@ -0,0 +1,21 @@
+#ifndef __KF_IO_LINUX_H__
+#define __KF_IO_LINUX_H__
+
+#include "io.h"
+
+class Console : public IO {
+public:
+	~Console() {};
+	char	rdch(void);
+	void	wrch(char c);
+
+	// Buffer I/O.
+	void	rdbuf(char *buf, size_t len, bool stopat, char stopch);
+	void	wrbuf(char *buf, size_t len);
+
+	// Line I/O
+	bool	rdln(char *buf, size_t len);
+private:
+};
+
+#endif // __KF_IO_LINUX_H__
diff --git a/misc/kf/io.h b/misc/kf/io.h
index ed14085..bbc3a0a 100644
--- a/misc/kf/io.h
+++ b/misc/kf/io.h
@@ -3,8 +3,25 @@
 
 // TODO(kyle): make this selectable by architecture.
 
-class IO {
+#ifdef __linux__
+#include <stddef.h>
+#endif
 
+class IO {
+public:
+	// Virtual destructor is required in all ABCs.
+	virtual ~IO() {};
+
+	// Building block methods.
+	virtual char	rdch(void) = 0;
+	virtual void	wrch(char c) = 0;
+
+	// Buffer I/O.
+	virtual void	rdbuf(char *buf, size_t len, bool stopat, char stopch) = 0;
+	virtual void	wrbuf(char *buf, size_t len) = 0;
+
+	// Line I/O
+	virtual bool	rdln(char *buf, size_t len) = 0;
 };
 
 #endif // __KF_IO_H__
\ No newline at end of file
diff --git a/misc/kf/kf.cc b/misc/kf/kf.cc
index abb3494..0a79085 100644
--- a/misc/kf/kf.cc
+++ b/misc/kf/kf.cc
@@ -1,8 +1,26 @@
 #include "io.h"
+#ifdef __linux__
+#include "linux.h"
+#endif // __linux__
 
+static void
+repl(IO &interface)
+{
+	static char lbuf[81];
+
+	while (true) {
+		interface.rdln(lbuf, 80);
+	}
+
+	return;
+}
 
 int
 main(void)
 {
+#ifdef __linux__
+	Console interface;
+#endif
+	repl(interface);
 	return 0;
 }
\ No newline at end of file
diff --git a/misc/kf/linux.h b/misc/kf/linux.h
new file mode 100644
index 0000000..79fb71e
--- /dev/null
+++ b/misc/kf/linux.h
@@ -0,0 +1,12 @@
+#ifndef __KF_LINUX_H__
+#define __KF_LINUX_H__
+
+#include <stdint.h>
+
+// build support for linux
+#include "io-linux.h"
+
+constexpr uint8_t STACK_SIZE = 128;
+
+
+#endif // __KF_LINUX_H__
\ No newline at end of file