1 files changed, 18 insertions, 12 deletions
diff --git a/src/cmd/sort.zig b/src/cmd/sort.zig
index 0f73940..79616e9 100644
--- a/src/cmd/sort.zig
+++ b/src/cmd/sort.zig
@@ -18,18 +18,24 @@ pub const Sort = struct {
             lines.deinit();
         }
 
-        // Read input lines
-        if (ctx.input_source) |source| {
-            // Read from input redirection
-            while (try source.readLine(ctx.allocator)) |line| {
-                try lines.append(line);
-            }
-        } else {
-            // Read from stdin (simplified - just show message)
-            const msg = "SORT: Use input redirection (< file.txt) to sort file contents\n";
-            var writer = ctx.output_writer;
-            try writer.write(msg);
-            return CommandStatus{ .Code = 0 };
+        // Read input lines from unified input reader
+        var reader = ctx.input_reader;
+
+        // Check if we're reading from stdin vs file redirection for DOS-authentic behavior
+        switch (ctx.input_reader) {
+            .stdin => {
+                // Reading from interactive stdin - show usage message (DOS behavior)
+                const msg = "SORT: Use input redirection (< file.txt) to sort file contents\n";
+                var writer = ctx.output_writer;
+                try writer.write(msg);
+                return CommandStatus{ .Code = 0 };
+            },
+            .source => {
+                // Read from input redirection
+                while (try reader.readLine(ctx.allocator)) |line| {
+                    try lines.append(line);
+                }
+            },
         }
 
         // Sort the lines