diff --git a/MiniScript-cpp/src/ShellIntrinsics.cpp b/MiniScript-cpp/src/ShellIntrinsics.cpp
index 0c61474..c39b6c2 100644
--- a/MiniScript-cpp/src/ShellIntrinsics.cpp
+++ b/MiniScript-cpp/src/ShellIntrinsics.cpp
@@ -749,7 +749,7 @@ static IntrinsicResult intrinsic_readLines(Context *context, IntrinsicResult par
 			}
 		}
 		if (lineStart < bytesRead) {
-			partialLine = String(&buf[lineStart], bytesRead - lineStart);
+			partialLine += String(&buf[lineStart], bytesRead - lineStart);
 		}
 	}
 	if (!partialLine.empty()) list.Add(partialLine);