diff --git a/common.go b/common.go
index f6b97a8..55bb7d9 100644
--- a/common.go
+++ b/common.go
@@ -929,6 +929,8 @@ var LanguagesByExtension = map[string][]string{
 }
 
 func init() {
+	LanguagesByExtension[".cgi"] = []string{OtherLanguage}
+	LanguagesByExtension[".fcgi"] = []string{OtherLanguage}
 	ExtensionsByLanguage = reverseStringListMap(LanguagesByExtension)
 }
 
diff --git a/content.go b/content.go
index 46a96c7..a6523f1 100644
--- a/content.go
+++ b/content.go
@@ -23,27 +23,32 @@ var matchers = map[string]languageMatcher{
 	".cls":  clsExtLanguage,
 	".m":    mExtLanguage,
 	".ms":   msExtLanguage,
+	".md":   mdExtLanguage,
+	".fs":   fsExtLanguage,
 	".h":    hExtLanguage,
+	".hh":   hhExtLanguage,
 	".l":    lExtLanguage,
 	".n":    nExtLanguage,
 	".lisp": lispExtLanguage,
 	".lsp":  lispExtLanguage,
 	".pm":   pmExtLanguage,
 	".t":    pmExtLanguage,
+	".rs":   rsExtLanguage,
 	".pl":   plExtLanguage,
 	".pro":  proExtLanguage,
 	".toc":  tocExtLanguage,
+	".sls":  slsExtLanguage,
 }
 
 var (
 	cPlusPlusMatcher = substring.BytesOr(
-		substring.BytesRegexp(`^\s*template\s*<`),
-		substring.BytesRegexp(`^\s*#\s*include <(cstdint|string|vector|map|list|array|bitset|queue|stack|forward_list|unordered_map|unordered_set|(i|o|io)stream)>`),
-		substring.BytesRegexp(`^[ \t]*try`),
-		substring.BytesRegexp(`^[ \t]*(class|(using[ \t]+)?namespace)\s+\w+`),
-		substring.BytesRegexp(`^[ \t]*(private|public|protected):$`),
+		substring.BytesRegexp(`\s*template\s*<`),
+		substring.BytesRegexp(`\s*#\s*include <(cstdint|string|vector|map|list|array|bitset|queue|stack|forward_list|unordered_map|unordered_set|(i|o|io)stream)>`),
+		substring.BytesRegexp(`\n[ \t]*try`),
+		substring.BytesRegexp(`\n[ \t]*(class|(using[ \t]+)?namespace)\s+\w+`),
+		substring.BytesRegexp(`\n[ \t]*(private|public|protected):$`),
 		substring.BytesRegexp(`std::\w+`),
-		substring.BytesRegexp(`^[ \t]*catch\s*`),
+		substring.BytesRegexp(`[ \t]*catch\s*`),
 	)
 )
 
@@ -55,6 +60,20 @@ func incExtLanguage(input []byte) (string, bool) {
 	return OtherLanguage, true
 }
 
+func fsExtLanguage(input []byte) (string, bool) {
+	if substring.BytesRegexp(`\n(: |new-device)`).Match(input) {
+		return "Forth", true
+	} else if substring.BytesRegexp(`\s*(#light|import|let|module|namespace|open|type)`).Match(input) {
+		return "F#", true
+	} else if substring.BytesRegexp(`(#version|precision|uniform|varying|vec[234])`).Match(input) {
+		return "GLSL", true
+	} else if substring.BytesRegexp(`#include|#pragma\s+(rs|version)|__attribute__`).Match(input) {
+		return "Filterscript", true
+	}
+
+	return OtherLanguage, true
+}
+
 func hExtLanguage(input []byte) (string, bool) {
 	if objectiveCMatcher.Match(input) {
 		return "Objective-C", true
@@ -65,6 +84,16 @@ func hExtLanguage(input []byte) (string, bool) {
 	return "C", true
 }
 
+func hhExtLanguage(input []byte) (string, bool) {
+	if substring.BytesRegexp(`^<\?(?:hh)?`).Match(input) {
+		return "Hack", true
+	} else if cPlusPlusMatcher.Match(input) {
+		return "C++", true
+	}
+
+	return OtherLanguage, false
+}
+
 func msExtLanguage(input []byte) (string, bool) {
 	if substring.BytesRegexp(`[.'][a-z][a-z](\s|$)`).Match(input) {
 		return "Groff", true
@@ -179,6 +208,16 @@ func mExtLanguage(input []byte) (string, bool) {
 	return OtherLanguage, false
 }
 
+func mdExtLanguage(input []byte) (string, bool) {
+	if substring.BytesRegexp(`\n[-a-z0-9=#!\*\[|]`).Match(input) {
+		return "Markdown", true
+	} else if substring.BytesRegexp(`\n(;;|\(define_)`).Match(input) {
+		return "GCC Machine Description", true
+	}
+
+	return OtherLanguage, false
+}
+
 var (
 	prologMatcher = substring.BytesRegexp(`^[^#]+:-`)
 	perlMatcher   = substring.BytesRegexp(`use strict|use\s+v?5\.`)
@@ -205,6 +244,16 @@ func pmExtLanguage(input []byte) (string, bool) {
 	return "Perl", false
 }
 
+func rsExtLanguage(input []byte) (string, bool) {
+	if substring.BytesRegexp(`(use |fn |mod |pub |macro_rules|impl|#!?\[)`).Match(input) {
+		return "Rust", true
+	} else if substring.BytesRegexp(`#include|#pragma\s+(rs|version)|__attribute__`).Match(input) {
+		return "RenderScript", true
+	}
+
+	return OtherLanguage, false
+}
+
 func proExtLanguage(input []byte) (string, bool) {
 	if prologMatcher.Match(input) {
 		return "Prolog", true
@@ -222,3 +271,13 @@ func tocExtLanguage(input []byte) (string, bool) {
 
 	return OtherLanguage, false
 }
+
+func slsExtLanguage(input []byte) (string, bool) {
+	if substring.BytesRegexp("## |@no-lib-strip@").Match(input) {
+		return "World of Warcraft Addon Data", true
+	} else if substring.BytesRegexp("(contentsline|defcounter|beamer|boolfalse)").Match(input) {
+		return "TeX", true
+	}
+
+	return OtherLanguage, false
+}
diff --git a/content_test.go b/content_test.go
index 65bc02b..fb86275 100644
--- a/content_test.go
+++ b/content_test.go
@@ -1,10 +1,12 @@
 package slinguist
 
 import (
+	"fmt"
 	"io/ioutil"
 	"os"
 	"path"
 	"path/filepath"
+	"text/tabwriter"
 
 	. "gopkg.in/check.v1"
 )
@@ -28,6 +30,7 @@ func (s *TSuite) TestGetLanguageByContentH(c *C) {
 	s.testGetLanguageByContent(c, "Prolog")
 	s.testGetLanguageByContent(c, "Perl")
 	s.testGetLanguageByContent(c, "Perl6")
+	s.testGetLanguageByContent(c, "Hack")
 }
 
 func (s *TSuite) testGetLanguageByContent(c *C, expected string) {
@@ -41,7 +44,6 @@ func (s *TSuite) testGetLanguageByContent(c *C, expected string) {
 		}
 
 		content, _ := ioutil.ReadFile(file)
-
 		obtained, _ := GetLanguageByContent(path.Base(file), content)
 		if obtained == OtherLanguage {
 			continue
@@ -50,3 +52,51 @@ func (s *TSuite) testGetLanguageByContent(c *C, expected string) {
 		c.Check(obtained, Equals, expected, Commentf(file))
 	}
 }
+
+func (s *TSuite) TestGetLanguageByContentLinguistCorpus(c *C) {
+	var total, failed, ok, other, unsafe int
+
+	w := new(tabwriter.Writer)
+	w.Init(os.Stdout, 0, 8, 0, '\t', 0)
+
+	filepath.Walk(".linguist/samples", func(path string, f os.FileInfo, err error) error {
+		if f.IsDir() {
+			if f.Name() == "filenames" {
+				return filepath.SkipDir
+			}
+			return nil
+		}
+
+		total++
+		expected := filepath.Base(filepath.Dir(path))
+		filename := filepath.Base(path)
+		content, _ := ioutil.ReadFile(path)
+
+		obtained, safe := GetLanguageByContent(filename, content)
+		if obtained == OtherLanguage {
+			other++
+		}
+
+		var status string
+		if expected == obtained {
+			status = "ok"
+			ok++
+		} else {
+			status = "failed"
+			failed++
+			if !safe {
+				unsafe++
+			}
+		}
+
+		fmt.Fprintf(w, "%s\t%s\t%s\t%v\t%s\n", filename, expected, obtained, safe, status)
+
+		return nil
+	})
+
+	fmt.Fprintln(w)
+	w.Flush()
+
+	fmt.Printf("total files: %d, ok: %d, failed: %d, unsafe: %d, other: %d\n", total, ok, failed, unsafe, other)
+
+}