diff --git a/bin/cmd.js b/bin/cmd.js
index 9f1aa80..e973c98 100755
--- a/bin/cmd.js
+++ b/bin/cmd.js
@@ -1,9 +1,16 @@
 #!/usr/bin/env node
 
+var fs = require('fs')
 var parser = require('@tap-format/parser')
 var formatAsSpec = require('../')
 
-var input$ = parser.observeStream(process.stdin)
+var stream = process.stdin
+
+if (process.argv[2]) {
+  stream = fs.createReadStream(process.argv[2])
+}
+
+var input$ = parser.observeStream(stream)
 
 formatAsSpec(input$).forEach(console.log.bind(console))