Added `pygmentize -C` option to guess a lexer from content

3 files changed, 27 insertions, 2 deletions

diff --git a/CHANGES b/CHANGES
index 578c09cb..a7f35602 100644
--- a/CHANGES
+++ b/CHANGES
@@ -11,6 +11,8 @@ Version 2.8.0
 -------------
 (not released yet)
 
+- Added `pygmentize -C` option to guess a lexer from content
+
 - Fix escapes in JavaScript backtick strings (#1679)
 - Make guessing prefer Python 3 lexer
 - Do not guess MIME or SQL without reason
diff --git a/pygments/cmdline.py b/pygments/cmdline.py
index 6a8a307a..cbd9d552 100644
--- a/pygments/cmdline.py
+++ b/pygments/cmdline.py
@@ -37,6 +37,7 @@ Usage: %s [-l <lexer> | -g] [-F <filter>[:<options>]] [-f <formatter>]
        %s -S <style> -f <formatter> [-a <arg>] [-O <options>] [-P <option=value>]
        %s -L [<which> ...]
        %s -N <filename>
+       %s -C
        %s -H <type> <name>
        %s -h | -V
 
@@ -92,6 +93,9 @@ The -N option guesses and prints out a lexer name based solely on
 the given filename. It does not take input or highlight anything.
 If no specific lexer can be determined "text" is returned.
 
+The -C option is like -N, but prints out a lexer name based solely on
+a given content from standard input.
+
 The -H option prints detailed help for the object <name> of type <type>,
 where <type> is one of "lexer", "formatter" or "filter".
 
@@ -292,6 +296,18 @@ def main_inner(popts, args, usage):
         print(lexer.aliases[0])
         return 0
 
+    # handle ``pygmentize -C``
+    infc = opts.pop('-C', None)
+    if infc is not None:
+        inp = sys.stdin.buffer.read()
+        try:
+            lexer = guess_lexer(inp, inencoding=inencoding)
+        except ClassNotFound:
+            lexer = TextLexer
+
+        print(lexer.aliases[0])
+        return 0
+
     # handle ``pygmentize -S``
     S_opt = opts.pop('-S', None)
     a_opt = opts.pop('-a', None)
@@ -545,10 +561,10 @@ def main(args=sys.argv):
     """
     Main command line entry point.
     """
-    usage = USAGE % ((args[0],) * 6)
+    usage = USAGE % ((args[0],) * 7)
 
     try:
-        popts, args = getopt.getopt(args[1:], "l:f:F:o:O:P:LS:a:N:vhVHgsx")
+        popts, args = getopt.getopt(args[1:], "l:f:F:o:O:P:LS:a:N:CvhVHgsx")
     except getopt.GetoptError:
         print(usage, file=sys.stderr)
         return 2
diff --git a/tests/test_cmdline.py b/tests/test_cmdline.py
index d740fccb..731729d9 100644
--- a/tests/test_cmdline.py
+++ b/tests/test_cmdline.py
@@ -220,6 +220,13 @@ def test_N_opt():
     assert 'text' == o.strip()
 
 
+def test_C_opt():
+    o = check_success('-C', stdin='#!python3\n')
+    assert 'python' == o.strip()
+    o = check_success('-C', stdin='x')
+    assert 'text' == o.strip()
+
+
 def test_invalid_opts():
     for opts in [
         ('-X',),