Don't parse if there are no flags.

README.md

@@ -68,7 +68,7 @@ Parameter        | Description                   |  Type
 :--------------- |:----------------------------- | :-------------------
 paths            | The file paths.               | String[]
 output           | The standard output or file.  | [IOSink](https://api.dart.dev/dart-io/IOSink-class.html)
-input            | The standard input.           | Stream<List\<int\>\>?
+input            | The standard input.           | [Stream](https://api.dart.dev/dart-io/Stdin-class.html)
 showEnds         | Same as `-e`                  | bool
 numberNonBlank   | Same as `-b`                  | bool
 showLineNumbers  | Same as `-n`                  | bool

doc/api/index.html

@@ -94,7 +94,7 @@ if (result.isFailure) {
 }
 </code></pre>
 <p>The <code>cat</code> function supports the following parameters:</p>
-<table><thead><tr><th style="text-align: left;">Parameter</th><th style="text-align: left;">Description</th><th style="text-align: left;">Type</th></tr></thead><tbody><tr><td style="text-align: left;">paths</td><td style="text-align: left;">The file paths.</td><td style="text-align: left;">String[]</td></tr><tr><td style="text-align: left;">output</td><td style="text-align: left;">The standard output or file.</td><td style="text-align: left;"><a href="https://api.dart.dev/dart-io/IOSink-class.html">IOSink</a></td></tr><tr><td style="text-align: left;">input</td><td style="text-align: left;">The standard input.</td><td style="text-align: left;">Stream&lt;List&lt;int&gt;&gt;?</td></tr><tr><td style="text-align: left;">showEnds</td><td style="text-align: left;">Same as <code>-e</code></td><td style="text-align: left;">bool</td></tr><tr><td style="text-align: left;">numberNonBlank</td><td style="text-align: left;">Same as <code>-b</code></td><td style="text-align: left;">bool</td></tr><tr><td style="text-align: left;">showLineNumbers</td><td style="text-align: left;">Same as <code>-n</code></td><td style="text-align: left;">bool</td></tr><tr><td style="text-align: left;">showTabs</td><td style="text-align: left;">Same as <code>-T</code></td><td style="text-align: left;">bool</td></tr><tr><td style="text-align: left;">squeezeBlank</td><td style="text-align: left;">Same as <code>-s</code></td><td style="text-align: left;">bool</td></tr><tr><td style="text-align: left;">showNonPrinting</td><td style="text-align: left;">Same as <code>-v</code></td><td style="text-align: left;">bool</td></tr></tbody></table>
+<table><thead><tr><th style="text-align: left;">Parameter</th><th style="text-align: left;">Description</th><th style="text-align: left;">Type</th></tr></thead><tbody><tr><td style="text-align: left;">paths</td><td style="text-align: left;">The file paths.</td><td style="text-align: left;">String[]</td></tr><tr><td style="text-align: left;">output</td><td style="text-align: left;">The standard output or file.</td><td style="text-align: left;"><a href="https://api.dart.dev/dart-io/IOSink-class.html">IOSink</a></td></tr><tr><td style="text-align: left;">input</td><td style="text-align: left;">The standard input.</td><td style="text-align: left;"><a href="https://api.dart.dev/dart-io/Stdin-class.html">Stream</a></td></tr><tr><td style="text-align: left;">showEnds</td><td style="text-align: left;">Same as <code>-e</code></td><td style="text-align: left;">bool</td></tr><tr><td style="text-align: left;">numberNonBlank</td><td style="text-align: left;">Same as <code>-b</code></td><td style="text-align: left;">bool</td></tr><tr><td style="text-align: left;">showLineNumbers</td><td style="text-align: left;">Same as <code>-n</code></td><td style="text-align: left;">bool</td></tr><tr><td style="text-align: left;">showTabs</td><td style="text-align: left;">Same as <code>-T</code></td><td style="text-align: left;">bool</td></tr><tr><td style="text-align: left;">squeezeBlank</td><td style="text-align: left;">Same as <code>-s</code></td><td style="text-align: left;">bool</td></tr><tr><td style="text-align: left;">showNonPrinting</td><td style="text-align: left;">Same as <code>-v</code></td><td style="text-align: left;">bool</td></tr></tbody></table>
 <ul>
 <li><code>paths</code> and <code>output</code> are required.</li>
 <li><code>output</code> should be an <a href="https://api.dart.dev/dart-io/IOSink-class.html">IOSink</a> like <code>stdout</code> or a <a href="https://api.dart.dev/dart-io/File/openWrite.html">File</a> stream.</li>

lib/dcat.dart

@@ -120,64 +120,78 @@ Future<void> _writeStream(
     bool showNonPrinting) async {
   const tab = 9;
   int squeeze = 0;
+  final noFlags = !showEnds &&
+      !showLineNumbers &&
+      !numberNonBlank &&
+      !showTabs &&
+      !squeezeBlank &&
+      !showNonPrinting;
   final sb = StringBuffer();
   await stream.forEach((data) {
     sb.clear();
     for (final ch in utf8.decode(data).runes) {
-      if (lastLine.lastChar == _lineFeed) {
+      if (noFlags) {
-        if (squeezeBlank) {
+        sb.writeCharCode(ch);
-          if (ch == _lineFeed) {
+      } else {
-            if (squeeze >= 1) {
+        if (lastLine.lastChar == _lineFeed) {
-              lastLine.lastChar = ch;
+          if (squeezeBlank) {
+            if (ch == _lineFeed) {
+              if (squeeze >= 1) {
+                lastLine.lastChar = ch;
+                continue;
+              }
+              squeeze++;
+            } else {
+              squeeze = 0;
+            }
+          }
+          if (showLineNumbers || numberNonBlank) {
+            if (!numberNonBlank || ch != _lineFeed) {
+              sb
+                ..write('${++lastLine.lineNumber}'.padLeft(6))
+                ..write('\t');
+            }
+          }
+        }
+        lastLine.lastChar = ch;
+        if (ch == _lineFeed) {
+          if (showEnds) {
+            sb.write('\$');
+          }
+        } else if (ch == tab) {
+          if (showTabs) {
+            sb.write('^I');
+            continue;
+          }
+        } else if (showNonPrinting) {
+          if (ch >= 32) {
+            if (ch < 127) {
+              // ASCII
+              sb.writeCharCode(ch);
+              continue;
+            } else if (ch == 127) {
+              // NULL
+              sb.write('^?');
+              continue;
+            } else {
+              // UNICODE
+              sb
+                ..write('U+')
+                ..write(ch.toRadixString(16).padLeft(4, '0').toUpperCase());
               continue;
             }
-            squeeze++;
           } else {
-            squeeze = 0;
+            sb
-          }
+              ..write('^')
-        }
+              ..writeCharCode(ch + 64);
-        if (showLineNumbers || numberNonBlank) {
+            continue;
-          if (!numberNonBlank || ch != _lineFeed) {
-            sb.write('${++lastLine.lineNumber}'.padLeft(6) + '\t');
           }
         }
+        sb.writeCharCode(ch);
       }
-      lastLine.lastChar = ch;
-      if (ch == _lineFeed) {
-        if (showEnds) {
-          sb.write('\$');
-        }
-      } else if (ch == tab) {
-        if (showTabs) {
-          sb.write('^I');
-          continue;
-        }
-      } else if (showNonPrinting) {
-        if (ch >= 32) {
-          if (ch < 127) {
-            // ASCII
-            sb.writeCharCode(ch);
-            continue;
-          } else if (ch == 127) {
-            // NULL
-            sb.write('^?');
-            continue;
-          } else {
-            // UNICODE
-            sb.write('U+' + ch.toRadixString(16).padLeft(4, '0').toUpperCase());
-            continue;
-          }
-        } else {
-          sb
-            ..write('^')
-            ..writeCharCode(ch + 64);
-          continue;
-        }
-      }
-      sb.writeCharCode(ch);
     }
     if (sb.isNotEmpty) {
       out.write(sb);
     }
   });
-}
+}

test/dcat_test.dart

@@ -269,5 +269,13 @@ void main() {
       lines = await tmp.readAsLines();
       expect(lines.length, 2, reason: "two lines");
     });
+
+    test('Test cat file -', () async {
+      var tmp = tmpFile();
+      await cat([sampleFile, '-'], tmp.openWrite(),
+          input: mockStdin(text: '\n$sampleText'));
+      var lines = await tmp.readAsLines();
+      expect(lines.last, equals(sampleText));
+    });
   });
-}
+}