include string.h
diff --git a/lsof.c b/lsof.c
index 99891db..f5a5e96 100644
--- a/lsof.c
+++ b/lsof.c
@@ -36,6 +36,7 @@
 #include <stdio.h>
 #include <stdlib.h>
 #include <unistd.h>
+#include <string.h>
 
 #define BUF_MAX 1024
 #define CMD_DISPLAY_MAX 10