diff --git a/src/controller.rs b/src/controller.rs
index ecef81eb..51581677 100644
--- a/src/controller.rs
+++ b/src/controller.rs
@@ -12,7 +12,7 @@ use crate::line_range::{LineRanges, RangeCheckResult};
 use crate::output::OutputType;
 #[cfg(feature = "paging")]
 use crate::paging::PagingMode;
-use crate::printer::{InteractivePrinter, Printer, SimplePrinter};
+use crate::printer::{InteractivePrinter, OutputHandle, Printer, SimplePrinter};
 
 use clircle::{Clircle, Identifier};
 
@@ -26,13 +26,18 @@ impl<'b> Controller<'b> {
         Controller { config, assets }
     }
 
-    pub fn run(&self, inputs: Vec<Input>) -> Result<bool> {
-        self.run_with_error_handler(inputs, default_error_handler)
+    pub fn run(
+        &self,
+        inputs: Vec<Input>,
+        output_buffer: Option<&mut dyn std::fmt::Write>,
+    ) -> Result<bool> {
+        self.run_with_error_handler(inputs, output_buffer, default_error_handler)
     }
 
     pub fn run_with_error_handler(
         &self,
         inputs: Vec<Input>,
+        output_buffer: Option<&mut dyn std::fmt::Write>,
         handle_error: impl Fn(&Error, &mut dyn Write),
     ) -> Result<bool> {
         let mut output_type;
@@ -74,7 +79,11 @@ impl<'b> Controller<'b> {
             clircle::Identifier::stdout()
         };
 
-        let writer = output_type.handle()?;
+        //let writer = output_type.handle()?;
+        let writer = output_buffer.map_or_else(
+            || OutputHandle::IoWrite(output_type.handle().unwrap()),
+            |buf| OutputHandle::FmtWrite(buf),
+        );
         let mut no_errors: bool = true;
         let stderr = io::stderr();
 
@@ -88,10 +97,15 @@ impl<'b> Controller<'b> {
                 self.print_input(input, writer, io::empty(), identifier, is_first)
             };
             if let Err(error) = result {
-                if attached_to_pager {
-                    handle_error(&error, writer);
-                } else {
-                    handle_error(&error, &mut stderr.lock());
+                match writer {
+                    OutputHandle::FmtWrite(writer) => todo!(),
+                    OutputHandle::IoWrite(writer) => {
+                        if attached_to_pager {
+                            handle_error(&error, writer);
+                        } else {
+                            handle_error(&error, &mut stderr.lock());
+                        }
+                    }
                 }
                 no_errors = false;
             }
@@ -103,7 +117,7 @@ impl<'b> Controller<'b> {
     fn print_input<R: BufRead>(
         &self,
         input: Input,
-        writer: &mut dyn Write,
+        writer: OutputHandle,
         stdin: R,
         stdout_identifier: Option<&Identifier>,
         is_first: bool,
@@ -164,7 +178,7 @@ impl<'b> Controller<'b> {
     fn print_file(
         &self,
         printer: &mut dyn Printer,
-        writer: &mut dyn Write,
+        writer: OutputHandle,
         input: &mut OpenedInput,
         add_header_padding: bool,
         #[cfg(feature = "git")] line_changes: &Option<LineChanges>,
@@ -202,7 +216,7 @@ impl<'b> Controller<'b> {
     fn print_file_ranges(
         &self,
         printer: &mut dyn Printer,
-        writer: &mut dyn Write,
+        writer: OutputHandle,
         reader: &mut InputReader,
         line_ranges: &LineRanges,
     ) -> Result<()> {
diff --git a/src/error.rs b/src/error.rs
index af0b9121..3579d4ff 100644
--- a/src/error.rs
+++ b/src/error.rs
@@ -7,6 +7,8 @@ pub enum Error {
     #[error(transparent)]
     Io(#[from] ::std::io::Error),
     #[error(transparent)]
+    Fmt(#[from] ::std::fmt::Error),
+    #[error(transparent)]
     SyntectError(#[from] ::syntect::Error),
     #[error(transparent)]
     SyntectLoadingError(#[from] ::syntect::LoadingError),
diff --git a/src/pretty_printer.rs b/src/pretty_printer.rs
index 02a7a519..121637f1 100644
--- a/src/pretty_printer.rs
+++ b/src/pretty_printer.rs
@@ -300,7 +300,7 @@ impl<'a> PrettyPrinter<'a> {
 
         // Run the controller
         let controller = Controller::new(&self.config, &self.assets);
-        controller.run(inputs.into_iter().map(|i| i.into()).collect())
+        controller.run(inputs.into_iter().map(|i| i.into()).collect(), None)
     }
 }
 
diff --git a/src/printer.rs b/src/printer.rs
index d46b23d1..328b993c 100644
--- a/src/printer.rs
+++ b/src/printer.rs
@@ -1,4 +1,5 @@
-use std::io::Write;
+use std::fmt;
+use std::io;
 use std::vec::Vec;
 
 use nu_ansi_term::Color::{Fixed, Green, Red, Yellow};
@@ -36,21 +37,52 @@ use crate::terminal::{as_terminal_escaped, to_ansi_color};
 use crate::vscreen::AnsiStyle;
 use crate::wrapping::WrappingMode;
 
+pub enum OutputHandle<'a> {
+    IoWrite(&'a mut dyn io::Write),
+    FmtWrite(&'a mut dyn fmt::Write),
+}
+
+macro_rules! write_handle {
+    ($dst:expr, $($arg:tt)*) => {
+        match $dst {
+            OutputHandle::IoWrite(ref mut handle) => {
+                write!(handle, $($arg)*).map_err(|e| Error::from(e))
+            }
+            OutputHandle::FmtWrite(ref mut handle) => {
+                write!(handle, $($arg)*).map_err(|e| Error::from(e))
+            }
+        }
+    }
+}
+
+macro_rules! writeln_handle {
+    ($dst:expr, $($arg:tt)*) => {
+        match $dst {
+            OutputHandle::IoWrite(ref mut handle) => {
+                writeln!(handle, $($arg)*).map_err(|e| Error::from(e))
+            }
+            OutputHandle::FmtWrite(ref mut handle) => {
+                writeln!(handle, $($arg)*).map_err(|e| Error::from(e))
+            }
+        }
+    }
+}
+
 pub(crate) trait Printer {
     fn print_header(
         &mut self,
-        handle: &mut dyn Write,
+        handle: OutputHandle,
         input: &OpenedInput,
         add_header_padding: bool,
     ) -> Result<()>;
-    fn print_footer(&mut self, handle: &mut dyn Write, input: &OpenedInput) -> Result<()>;
+    fn print_footer(&mut self, handle: OutputHandle, input: &OpenedInput) -> Result<()>;
 
-    fn print_snip(&mut self, handle: &mut dyn Write) -> Result<()>;
+    fn print_snip(&mut self, handle: OutputHandle) -> Result<()>;
 
     fn print_line(
         &mut self,
         out_of_range: bool,
-        handle: &mut dyn Write,
+        handle: OutputHandle,
         line_number: usize,
         line_buffer: &[u8],
     ) -> Result<()>;
@@ -69,25 +101,25 @@ impl<'a> SimplePrinter<'a> {
 impl<'a> Printer for SimplePrinter<'a> {
     fn print_header(
         &mut self,
-        _handle: &mut dyn Write,
+        _handle: OutputHandle,
         _input: &OpenedInput,
         _add_header_padding: bool,
     ) -> Result<()> {
         Ok(())
     }
 
-    fn print_footer(&mut self, _handle: &mut dyn Write, _input: &OpenedInput) -> Result<()> {
+    fn print_footer(&mut self, _handle: OutputHandle, _input: &OpenedInput) -> Result<()> {
         Ok(())
     }
 
-    fn print_snip(&mut self, _handle: &mut dyn Write) -> Result<()> {
+    fn print_snip(&mut self, _handle: OutputHandle) -> Result<()> {
         Ok(())
     }
 
     fn print_line(
         &mut self,
         out_of_range: bool,
-        handle: &mut dyn Write,
+        handle: OutputHandle,
         _line_number: usize,
         line_buffer: &[u8],
     ) -> Result<()> {
@@ -98,9 +130,12 @@ impl<'a> Printer for SimplePrinter<'a> {
                     self.config.tab_width,
                     self.config.nonprintable_notation,
                 );
-                write!(handle, "{}", line)?;
+                write_handle!(handle, "{}", line)?;
             } else {
-                handle.write_all(line_buffer)?
+                match handle {
+                    OutputHandle::IoWrite(handle) => handle.write_all(line_buffer)?,
+                    OutputHandle::FmtWrite(handle) => todo!(),
+                }
             };
         }
         Ok(())
@@ -218,8 +253,8 @@ impl<'a> InteractivePrinter<'a> {
         })
     }
 
-    fn print_horizontal_line_term(&mut self, handle: &mut dyn Write, style: Style) -> Result<()> {
-        writeln!(
+    fn print_horizontal_line_term(&mut self, handle: OutputHandle, style: Style) -> Result<()> {
+        writeln_handle!(
             handle,
             "{}",
             style.paint("─".repeat(self.config.term_width))
@@ -227,13 +262,13 @@ impl<'a> InteractivePrinter<'a> {
         Ok(())
     }
 
-    fn print_horizontal_line(&mut self, handle: &mut dyn Write, grid_char: char) -> Result<()> {
+    fn print_horizontal_line(&mut self, handle: OutputHandle, grid_char: char) -> Result<()> {
         if self.panel_width == 0 {
             self.print_horizontal_line_term(handle, self.colors.grid)?;
         } else {
             let hline = "─".repeat(self.config.term_width - (self.panel_width + 1));
             let hline = format!("{}{}{}", "─".repeat(self.panel_width), grid_char, hline);
-            writeln!(handle, "{}", self.colors.grid.paint(hline))?;
+            writeln_handle!(handle, "{}", self.colors.grid.paint(hline))?;
         }
 
         Ok(())
@@ -257,9 +292,9 @@ impl<'a> InteractivePrinter<'a> {
         }
     }
 
-    fn print_header_component_indent(&mut self, handle: &mut dyn Write) -> std::io::Result<()> {
+    fn print_header_component_indent(&mut self, handle: OutputHandle) -> Result<()> {
         if self.config.style_components.grid() {
-            write!(
+            write_handle!(
                 handle,
                 "{}{}",
                 " ".repeat(self.panel_width),
@@ -268,7 +303,7 @@ impl<'a> InteractivePrinter<'a> {
                     .paint(if self.panel_width > 0 { "│ " } else { "" }),
             )
         } else {
-            write!(handle, "{}", " ".repeat(self.panel_width))
+            write_handle!(handle, "{}", " ".repeat(self.panel_width))
         }
     }
 
@@ -285,7 +320,7 @@ impl<'a> InteractivePrinter<'a> {
 impl<'a> Printer for InteractivePrinter<'a> {
     fn print_header(
         &mut self,
-        handle: &mut dyn Write,
+        handle: OutputHandle,
         input: &OpenedInput,
         add_header_padding: bool,
     ) -> Result<()> {
@@ -295,7 +330,7 @@ impl<'a> Printer for InteractivePrinter<'a> {
 
         if !self.config.style_components.header() {
             if Some(ContentType::BINARY) == self.content_type && !self.config.show_nonprintable {
-                writeln!(
+                writeln_handle!(
                     handle,
                     "{}: Binary content from {} will not be printed to the terminal \
                      (but will be present if the output of 'bat' is piped). You can use 'bat -A' \
@@ -343,7 +378,7 @@ impl<'a> Printer for InteractivePrinter<'a> {
         } else {
             // Only pad space between files, if we haven't already drawn a horizontal rule
             if add_header_padding && !self.config.style_components.rule() {
-                writeln!(handle)?;
+                writeln_handle!(handle,)?;
             }
         }
 
@@ -351,7 +386,7 @@ impl<'a> Printer for InteractivePrinter<'a> {
             self.print_header_component_indent(handle)?;
 
             match component {
-                StyleComponent::HeaderFilename => writeln!(
+                StyleComponent::HeaderFilename => writeln_handle!(
                     handle,
                     "{}{}{}",
                     description
@@ -367,7 +402,7 @@ impl<'a> Printer for InteractivePrinter<'a> {
                         .size
                         .map(|s| format!("{}", ByteSize(s)))
                         .unwrap_or_else(|| "-".into());
-                    writeln!(handle, "Size: {}", self.colors.header_value.paint(bsize))
+                    writeln_handle!(handle, "Size: {}", self.colors.header_value.paint(bsize))
                 }
                 _ => Ok(()),
             }
@@ -384,7 +419,7 @@ impl<'a> Printer for InteractivePrinter<'a> {
         Ok(())
     }
 
-    fn print_footer(&mut self, handle: &mut dyn Write, _input: &OpenedInput) -> Result<()> {
+    fn print_footer(&mut self, handle: OutputHandle, _input: &OpenedInput) -> Result<()> {
         if self.config.style_components.grid()
             && (self.content_type.map_or(false, |c| c.is_text()) || self.config.show_nonprintable)
         {
@@ -394,7 +429,7 @@ impl<'a> Printer for InteractivePrinter<'a> {
         }
     }
 
-    fn print_snip(&mut self, handle: &mut dyn Write) -> Result<()> {
+    fn print_snip(&mut self, handle: OutputHandle) -> Result<()> {
         let panel = self.create_fake_panel(" ...");
         let panel_count = panel.chars().count();
 
@@ -407,13 +442,13 @@ impl<'a> Printer for InteractivePrinter<'a> {
         let snip_right =
             " ─".repeat((self.config.term_width - panel_count - snip_left_count - title_count) / 2);
 
-        writeln!(
+        writeln_handle!(
             handle,
             "{}",
             self.colors
                 .grid
                 .paint(format!("{}{}{}{}", panel, snip_left, title, snip_right))
-        )?;
+        );
 
         Ok(())
     }
@@ -421,7 +456,7 @@ impl<'a> Printer for InteractivePrinter<'a> {
     fn print_line(
         &mut self,
         out_of_range: bool,
-        handle: &mut dyn Write,
+        handle: OutputHandle,
         line_number: usize,
         line_buffer: &[u8],
     ) -> Result<()> {
@@ -508,7 +543,7 @@ impl<'a> Printer for InteractivePrinter<'a> {
                 .map(|d| d.generate(line_number, false, self));
 
             for deco in decorations {
-                write!(handle, "{} ", deco.text)?;
+                write_handle!(handle, "{} ", deco.text)?;
                 cursor_max -= deco.width + 1;
             }
         }
@@ -526,7 +561,7 @@ impl<'a> Printer for InteractivePrinter<'a> {
                         // ANSI escape passthrough.
                         (ansi, true) => {
                             self.ansi_style.update(ansi);
-                            write!(handle, "{}", ansi)?;
+                            write_handle!(handle, "{}", ansi)?;
                         }
 
                         // Regular text.
@@ -534,7 +569,7 @@ impl<'a> Printer for InteractivePrinter<'a> {
                             let text = &*self.preprocess(text, &mut cursor_total);
                             let text_trimmed = text.trim_end_matches(|c| c == '\r' || c == '\n');
 
-                            write!(
+                            write_handle!(
                                 handle,
                                 "{}",
                                 as_terminal_escaped(
@@ -559,9 +594,13 @@ impl<'a> Printer for InteractivePrinter<'a> {
                                     } else {
                                         0
                                     };
-                                    write!(handle, "{}", ansi_style.paint(" ".repeat(width)))?;
+                                    write_handle!(
+                                        handle,
+                                        "{}",
+                                        ansi_style.paint(" ".repeat(width))
+                                    )?;
                                 }
-                                write!(handle, "{}", &text[text_trimmed.len()..])?;
+                                write_handle!(handle, "{}", &text[text_trimmed.len()..])?;
                             }
                         }
                     }
@@ -569,7 +608,7 @@ impl<'a> Printer for InteractivePrinter<'a> {
             }
 
             if !self.config.style_components.plain() && line.bytes().next_back() != Some(b'\n') {
-                writeln!(handle)?;
+                writeln_handle!(handle,)?;
             }
         } else {
             for &(style, region) in &regions {
@@ -579,7 +618,7 @@ impl<'a> Printer for InteractivePrinter<'a> {
                         // ANSI escape passthrough.
                         (ansi, true) => {
                             self.ansi_style.update(ansi);
-                            write!(handle, "{}", ansi)?;
+                            write_handle!(handle, "{}", ansi)?;
                         }
 
                         // Regular text.
@@ -624,7 +663,7 @@ impl<'a> Printer for InteractivePrinter<'a> {
                                     }
 
                                     // It wraps.
-                                    write!(
+                                    write_handle!(
                                         handle,
                                         "{}\n{}",
                                         as_terminal_escaped(
@@ -650,7 +689,7 @@ impl<'a> Printer for InteractivePrinter<'a> {
 
                             // flush the buffer
                             cursor += current_width;
-                            write!(
+                            write_handle!(
                                 handle,
                                 "{}",
                                 as_terminal_escaped(
@@ -673,18 +712,18 @@ impl<'a> Printer for InteractivePrinter<'a> {
                     ..Default::default()
                 };
 
-                write!(
+                write_handle!(
                     handle,
                     "{}",
                     ansi_style.paint(" ".repeat(cursor_max - cursor))
                 )?;
             }
-            writeln!(handle)?;
+            writeln_handle!(handle,)?;
         }
 
         if highlight_this_line && self.config.theme == "ansi" {
             self.ansi_style.update("^[24m");
-            write!(handle, "\x1B[24m")?;
+            write_handle!(handle, "\x1B[24m")?;
         }
 
         Ok(())