fix(lexer): handle backslash-newline line continuation between tokens

crates/bashkit/src/parser/lexer.rs

@@ -231,6 +231,16 @@ impl<'a> Lexer<'a> {
         while let Some(ch) = self.peek_char() {
             if ch == ' ' || ch == '\t' {
                 self.advance();
+            } else if ch == '\\' {
+                // Check for backslash-newline (line continuation) between tokens
+                let mut lookahead = self.chars.clone();
+                lookahead.next(); // skip backslash
+                if lookahead.next() == Some('\n') {
+                    self.advance(); // consume backslash
+                    self.advance(); // consume newline
+                } else {
+                    break;
+                }
             } else {
                 break;
             }

crates/bashkit/tests/issue_289_test.rs

@@ -0,0 +1,22 @@
+//! Regression test for #289: backslash line continuation fails in some contexts
+
+use bashkit::Bash;
+
+#[tokio::test]
+async fn issue_289_backslash_continuation_if() {
+    let mut bash = Bash::new();
+    let r = bash
+        .exec(
+            "A=\"\"\nB=\"\"\nif [ -z \"$A\" ] || \\\n   [ -z \"$B\" ]; then\n    echo missing\nfi",
+        )
+        .await
+        .unwrap();
+    assert_eq!(r.stdout.trim(), "missing");
+}
+
+#[tokio::test]
+async fn issue_289_backslash_continuation_command() {
+    let mut bash = Bash::new();
+    let r = bash.exec("echo hello \\\n    world").await.unwrap();
+    assert_eq!(r.stdout.trim(), "hello world");
+}