Fix join in streamed --lines

src/bin/tuc.rs

@@ -671,6 +671,12 @@ fn read_and_cut_lines(
                         // we exhausted the use of that bound, move on
                         bounds_idx += 1;
                         add_newline_next = false;
+
+                        // if opt.join and it was not the last matching bound
+                        if opt.join && bounds_idx != opt.bounds.0.len() {
+                            stdout.write_all(&[opt.eol as u8])?;
+                        }
+
                         continue; // let's see if the next bound matches too
                     }
                 }

tests/cli.rs

@@ -153,6 +153,15 @@ fn it_cuts_on_lines() {
 
     let mut cmd = Command::cargo_bin(env!("CARGO_PKG_NAME")).unwrap();
 
+    let assert = cmd
+        .args(&["--lines", "3,1"])
+        .write_stdin("a\nb\nc")
+        .assert();
+
+    assert.success().stdout("ca");
+
+    let mut cmd = Command::cargo_bin(env!("CARGO_PKG_NAME")).unwrap();
+
     let assert = cmd
         .args(&["--lines", "2:3"])
         .write_stdin("a\nb\nc")
@@ -199,3 +208,24 @@ fn it_join_fields() {
 
     assert.success().stdout("a-c\n");
 }
+
+#[test]
+fn it_join_lines() {
+    let mut cmd = Command::cargo_bin(env!("CARGO_PKG_NAME")).unwrap();
+
+    let assert = cmd
+        .args(&["-l", "1,3", "-j"])
+        .write_stdin("a\nb\nc")
+        .assert();
+
+    assert.success().stdout("a\nc");
+
+    let mut cmd = Command::cargo_bin(env!("CARGO_PKG_NAME")).unwrap();
+
+    let assert = cmd
+        .args(&["-l", "3,1", "-j"])
+        .write_stdin("a\nb\nc")
+        .assert();
+
+    assert.success().stdout("c\na");
+}