update: userprog (tee, tsh, sleep, hex2bin)

userprog/hex2bin/Makefile

@@ -0,0 +1,15 @@
+TARGET = hex2bin
+SRCS = hex2bin.c
+CC = gcc
+CFLAGS = -static -Wall
+
+OUT_BIN ?= $(TARGET)
+
+all: $(OUT_BIN)
+
+$(OUT_BIN): $(SRCS)
+	@echo "   [CC] Compiling to $(OUT_BIN)..."
+	$(CC) $(CFLAGS) -o $@ $^
+
+clean:
+	rm -f $(TARGET)

userprog/hex2bin/hex2bin.c

@@ -0,0 +1,13 @@
+#include <stdio.h>
+
+// 사용법: echo "41 42 43" | hex2bin
+int main() {
+    int byte;
+    // 16진수(%x)로 정수를 읽어서
+    while (scanf("%x", &byte) == 1) {
+        // char(바이트) 형태로 stdout에 씀
+        unsigned char c = (unsigned char)byte;
+        fwrite(&c, 1, 1, stdout);
+    }
+    return 0;
+}