diff --git a/gclc.system/src/main/java/net/bigeon/gclc/system/ExecSystemCommand.java b/gclc.system/src/main/java/net/bigeon/gclc/system/ExecSystemCommand.java
index 4e1f675..b29521a 100644
--- a/gclc.system/src/main/java/net/bigeon/gclc/system/ExecSystemCommand.java
+++ b/gclc.system/src/main/java/net/bigeon/gclc/system/ExecSystemCommand.java
@@ -101,7 +101,10 @@ public class ExecSystemCommand extends Command {
         try (BufferedWriter writer = new BufferedWriter(new OutputStreamWriter(os))) {
             while (th.isAlive()) {
                 final String user = in.prompt();
-                writer.write(user + EOL);
+                // Avoid interruption being sent to process.
+                if (!user.isEmpty()) {
+                    writer.write(user + EOL);
+                }
             }
         } catch (final IOException e1) {
             throw new CommandRunException(CommandRunExceptionType.INTERACTION,