diff --git a/kernel/printf.c b/kernel/printf.c
index d20534c150..9326608da4 100644
--- a/kernel/printf.c
+++ b/kernel/printf.c
@@ -108,6 +108,8 @@ printf(char *fmt, ...)
       i += 2;
     } else if(c0 == 'p'){
       printptr(va_arg(ap, uint64));
+    } else if(c0 == 'c'){
+      putc(fd, va_arg(ap, int));
     } else if(c0 == 's'){
       if((s = va_arg(ap, char*)) == 0)
         s = "(null)";
diff --git a/user/printf.c b/user/printf.c
index 81787467fa..14cc9db0d8 100644
--- a/user/printf.c
+++ b/user/printf.c
@@ -47,7 +47,7 @@ printptr(int fd, uint64 x) {
     putc(fd, digits[x >> (sizeof(uint64) * 8 - 4)]);
 }
 
-// Print to the given fd. Only understands %d, %x, %p, %s.
+// Print to the given fd. Only understands %d, %x, %p, %c, %s.
 void
 vprintf(int fd, const char *fmt, va_list ap)
 {
@@ -93,6 +93,8 @@ vprintf(int fd, const char *fmt, va_list ap)
         i += 2;
       } else if(c0 == 'p'){
         printptr(fd, va_arg(ap, uint64));
+      } else if(c0 == 'c'){
+        putc(fd, va_arg(ap, int));
       } else if(c0 == 's'){
         if((s = va_arg(ap, char*)) == 0)
           s = "(null)";