Add --no-filename flag.

When this flag is set, a filename is never shown for a match.

Closes BurntSushi#20

doc/rg.1

@@ -175,6 +175,12 @@ This is the default when more than one file is searched.
 .RS
 .RE
 .TP
+.B \-\-no\-filename
+Never show the filename for a match.
+This is the default when one file is searched.
+.RS
+.RE
+.TP
 .B \-\-heading
 Show the file name above clusters of matches from each file.
 This is the default mode at a tty.

doc/rg.1.md

@@ -114,6 +114,10 @@ the raw speed of grep.
 : Prefix each match with the file name that contains it. This is the
   default when more than one file is searched.
 
+--no-filename
+: Never show the filename for a match. This is the default when
+  one file is searched.
+
 --heading
 : Show the file name above clusters of matches from each file.
   This is the default mode at a tty.

src/args.rs

@@ -114,6 +114,10 @@ Less common options:
         Prefix each match with the file name that contains it. This is the
         default when more than one file is searched.
 
+    --no-filename
+        Never show the filename for a match. This is the default when
+        one file is searched.
+
     --heading
         Show the file name above clusters of matches from each file.
         This is the default mode at a tty.
@@ -203,6 +207,7 @@ pub struct RawArgs {
     flag_no_ignore_parent: bool,
     flag_no_line_number: bool,
     flag_no_mmap: bool,
+    flag_no_filename: bool,
     flag_pretty: bool,
     flag_quiet: bool,
     flag_regexp: Vec<String>,
@@ -321,10 +326,13 @@ impl RawArgs {
                 self.flag_color == "always"
             };
         let eol = b'\n';
+
         let mut with_filename = self.flag_with_filename;
         if !with_filename {
             with_filename = paths.len() > 1 || paths[0].is_dir();
         }
+        with_filename = with_filename && !self.flag_no_filename;
+
         let mut btypes = TypesBuilder::new();
         btypes.add_defaults();
         try!(self.add_types(&mut btypes));

tests/tests.rs

@@ -652,6 +652,18 @@ clean!(regression_65, "xyz", ".", |wd: WorkDir, mut cmd: Command| {
     wd.assert_err(&mut cmd);
 });
 
+// See: https://github.com/BurntSushi/ripgrep/issues/20
+sherlock!(feature_20, "Sherlock", ".", |wd: WorkDir, mut cmd: Command| {
+    cmd.arg("--no-filename");
+
+    let lines: String = wd.stdout(&mut cmd);
+    let expected = "\
+For the Doctor Watsons of this world, as opposed to the Sherlock
+be, to a very large extent, the result of luck. Sherlock Holmes
+";
+    assert_eq!(lines, expected);
+});
+
 #[test]
 fn binary_nosearch() {
     let wd = WorkDir::new("binary_nosearch");