diff --git a/README.md b/README.md
index 019de0b..f816b89 100644
--- a/README.md
+++ b/README.md
@@ -331,7 +331,8 @@ Analogous to the redirect-and-append operator `>>` in Unix, but works with JavaS
 those returned by `cat`, `grep`, etc).
 
 
-### sed([options,] search_regex, replacement, file)
+### sed([options,] search_regex, replacement, file [, file ...])
+### sed([options,] search_regex, replacement, file_array)
 Available options:
 
 + `-i`: Replace contents of 'file' in-place. _Note that no backups will be created!_
@@ -343,7 +344,7 @@ sed('-i', 'PROGRAM_VERSION', 'v0.1.3', 'source.js');
 sed(/.*DELETE_THIS_LINE.*\n/, '', 'source.js');
 ```
 
-Reads an input string from `file` and performs a JavaScript `replace()` on the input
+Reads an input string from `files` and performs a JavaScript `replace()` on the input
 using the given search regex and replacement string or function. Returns the new string after replacement.
 
 
diff --git a/src/sed.js b/src/sed.js
index e1aeb01..baa385b 100644
--- a/src/sed.js
+++ b/src/sed.js
@@ -2,7 +2,8 @@ var common = require('./common');
 var fs = require('fs');
 
 //@
-//@ ### sed([options,] search_regex, replacement, file)
+//@ ### sed([options,] search_regex, replacement, file [, file ...])
+//@ ### sed([options,] search_regex, replacement, file_array)
 //@ Available options:
 //@
 //@ + `-i`: Replace contents of 'file' in-place. _Note that no backups will be created!_
@@ -14,9 +15,9 @@ var fs = require('fs');
 //@ sed(/.*DELETE_THIS_LINE.*\n/, '', 'source.js');
 //@ ```
 //@
-//@ Reads an input string from `file` and performs a JavaScript `replace()` on the input
+//@ Reads an input string from `files` and performs a JavaScript `replace()` on the input
 //@ using the given search regex and replacement string or function. Returns the new string after replacement.
-function _sed(options, regex, replacement, file) {
+function _sed(options, regex, replacement, files) {
   options = common.parseOptions(options, {
     'i': 'inplace'
   });
@@ -32,19 +33,32 @@ function _sed(options, regex, replacement, file) {
   if (typeof regex === 'string')
     regex = RegExp(regex);
 
-  if (!file)
-    common.error('no file given');
+  if (!files)
+    common.error('no files given');
 
-  if (!fs.existsSync(file))
-    common.error('no such file or directory: ' + file);
+  if (typeof files === 'string')
+    files = [].slice.call(arguments, 3);
+  // if it's array leave it as it is
 
-  var result = fs.readFileSync(file, 'utf8').split('\n').map(function (line) {
-    return line.replace(regex, replacement);
-  }).join('\n');
+  files = common.expand(files);
 
-  if (options.inplace)
-    fs.writeFileSync(file, result, 'utf8');
+  var sed = [];
+  files.forEach(function(file) {
+    if (!fs.existsSync(file)) {
+      common.error('no such file or directory: ' + file, true);
+      return;
+    }
 
-  return common.ShellString(result);
+    var result = fs.readFileSync(file, 'utf8').split('\n').map(function (line) {
+      return line.replace(regex, replacement);
+    }).join('\n');
+
+    sed.push(result);
+
+    if (options.inplace)
+      fs.writeFileSync(file, result, 'utf8');
+  });
+
+  return common.ShellString(sed.join('\n'));
 }
 module.exports = _sed;
diff --git a/test/sed.js b/test/sed.js
index 469a69e..98a9ba5 100644
--- a/test/sed.js
+++ b/test/sed.js
@@ -21,8 +21,15 @@ assert.ok(shell.error());
 shell.sed(/asdf/g, 'nada'); // too few args
 assert.ok(shell.error());
 
-assert.equal(fs.existsSync('/asdfasdf'), false); // sanity check
-shell.sed(/asdf/g, 'nada', '/asdfasdf'); // no such file
+assert.equal(fs.existsSync('asdfasdf'), false); // sanity check
+shell.sed(/asdf/g, 'nada', 'asdfasdf'); // no such file
+assert.ok(shell.error());
+
+// if at least one file is missing, this should be an error
+shell.cp('-f', 'resources/file1', 'tmp/file1');
+assert.equal(fs.existsSync('asdfasdf'), false); // sanity check
+assert.equal(fs.existsSync('tmp/file1'), true); // sanity check
+shell.sed(/asdf/g, 'nada', 'tmp/file1', 'asdfasdf');
 assert.ok(shell.error());
 
 //
@@ -74,4 +81,24 @@ var result = shell.sed('l*\\.js', '', 'resources/grep/file');
 assert.ok(!shell.error());
 assert.equal(result, 'alphaaaaaaabeta\nhowareyou\nalphbeta\nthis line ends in\n\n');
 
+shell.cp('-f', 'resources/file1', 'tmp/file1');
+shell.cp('-f', 'resources/file2', 'tmp/file2');
+
+// multiple file names
+var result = shell.sed('test', 'hello', 'tmp/file1', 'tmp/file2');
+assert.equal(shell.error(), null);
+assert.equal(result, 'hello1\nhello2');
+
+// array of file names (and try it out with a simple regex)
+var result = shell.sed(/t.*st/, 'hello', ['tmp/file1', 'tmp/file2']);
+assert.equal(shell.error(), null);
+assert.equal(result, 'hello1\nhello2');
+
+// multiple file names, with in-place-replacement
+var result = shell.sed('-i', 'test', 'hello', ['tmp/file1', 'tmp/file2']);
+assert.equal(shell.error(), null);
+assert.equal(result, 'hello1\nhello2');
+assert.equal(shell.cat('tmp/file1'), 'hello1');
+assert.equal(shell.cat('tmp/file2'), 'hello2');
+
 shell.exit(123);