diff --git a/docs/instrument.md b/docs/instrument.md
index af19b6daa..bce1a3b4c 100644
--- a/docs/instrument.md
+++ b/docs/instrument.md
@@ -20,6 +20,8 @@ For example, `nyc instrument . ./output` will produce instrumented versions of a
 
 The `--delete` option will remove the existing output directory before instrumenting.
 
+The `--in-place` option will allow you to run the instrument command.
+
 The `--complete-copy` option will copy all remaining files from the `input` directory to the `output` directory.
 When using `--complete-copy` nyc will not copy the contents of a `.git` folder to the output directory.
 
@@ -27,8 +29,8 @@ When using `--complete-copy` nyc will not copy the contents of a `.git` folder t
 
 ## Streaming instrumentation
 
-`nyc instrument` will stream instrumented source directly to `stdout`, that can then be piped to another process.
-You can use this behaviour to create a server that can instrument files on request.
+`nyc instrument <input>` will stream instrumented source directly to `stdout` and that output can then be piped to another process.
+You can use this behaviour to create a server that dynamically instruments files on request.
 The following example shows streaming instrumentation middleware capable of instrumenting files on request.
 
 ```javascript
diff --git a/lib/commands/instrument.js b/lib/commands/instrument.js
index 553a1af7b..541878b2c 100644
--- a/lib/commands/instrument.js
+++ b/lib/commands/instrument.js
@@ -31,32 +31,37 @@ exports.builder = function (yargs) {
     .option('source-map', {
       default: true,
       type: 'boolean',
-      description: 'should nyc detect and handle source maps?'
+      describe: 'should nyc detect and handle source maps?'
     })
     .option('produce-source-map', {
       default: false,
       type: 'boolean',
-      description: "should nyc's instrumenter produce source maps?"
+      describe: "should nyc's instrumenter produce source maps?"
     })
     .option('compact', {
       default: true,
       type: 'boolean',
-      description: 'should the output be compacted?'
+      describe: 'should the output be compacted?'
     })
     .option('preserve-comments', {
       default: true,
       type: 'boolean',
-      description: 'should comments be preserved in the output?'
+      describe: 'should comments be preserved in the output?'
     })
     .option('instrument', {
       default: true,
       type: 'boolean',
-      description: 'should nyc handle instrumentation?'
+      describe: 'should nyc handle instrumentation?'
+    })
+    .option('in-place', {
+      default: false,
+      type: 'boolean',
+      describe: 'should nyc run the instrumentation in place?'
     })
     .option('exit-on-error', {
       default: false,
       type: 'boolean',
-      description: 'should nyc exit when an instrumentation failure occurs?'
+      describe: 'should nyc exit when an instrumentation failure occurs?'
     })
     .option('include', {
       alias: 'n',
@@ -92,17 +97,22 @@ exports.builder = function (yargs) {
     .example('$0 instrument ./lib ./output', 'instrument all .js files in ./lib with coverage and output in ./output')
 }
 
+const errorExit = msg => {
+  console.error(`nyc instrument failed:  ${msg}`)
+  process.exitCode = 1
+}
+
 exports.handler = function (argv) {
-  if (argv.output && (path.resolve(argv.cwd, argv.input) === path.resolve(argv.cwd, argv.output))) {
-    console.error(`nyc instrument failed: cannot instrument files in place, <input> must differ from <output>`)
-    process.exitCode = 1
-    return
+  if (argv.output && !argv.inPlace && (path.resolve(argv.cwd, argv.input) === path.resolve(argv.cwd, argv.output))) {
+    return errorExit(`cannot instrument files in place, <input> must differ from <output>.  Set '--in-place' to force`)
   }
 
   if (path.relative(argv.cwd, path.resolve(argv.cwd, argv.input)).startsWith('..')) {
-    console.error(`nyc instrument failed: cannot instrument files outside of project root directory`)
-    process.exitCode = 1
-    return
+    return errorExit('cannot instrument files outside project root directory')
+  }
+
+  if (argv.delete && argv.inPlace) {
+    return errorExit(`cannot use '--delete' when instrumenting files in place`)
   }
 
   if (argv.delete && argv.output && argv.output.length !== 0) {
@@ -110,8 +120,7 @@ exports.handler = function (argv) {
     if (relPath !== '' && !relPath.startsWith('..')) {
       rimraf.sync(argv.output)
     } else {
-      console.error(`nyc instrument failed: attempt to delete '${process.cwd()}' or containing directory.`)
-      process.exit(1)
+      return errorExit(`attempt to delete '${process.cwd()}' or containing directory.`)
     }
   }
 
@@ -120,12 +129,11 @@ exports.handler = function (argv) {
     ? './lib/instrumenters/istanbul'
     : './lib/instrumenters/noop'
 
-  const nyc = new NYC(argv)
+  if (argv.inPlace) {
+    argv.output = argv.input
+    argv.completeCopy = false
+  }
 
-  nyc.instrumentAllFiles(argv.input, argv.output, err => {
-    if (err) {
-      console.error(err.message)
-      process.exitCode = 1
-    }
-  })
+  const nyc = new NYC(argv)
+  nyc.instrumentAllFiles(argv.input, argv.output, err => err ? errorExit(err.message) : null)
 }
diff --git a/tap-snapshots/test-nyc-integration.js-TAP.test.js b/tap-snapshots/test-nyc-integration.js-TAP.test.js
index 46353911f..5c7adcee6 100644
--- a/tap-snapshots/test-nyc-integration.js-TAP.test.js
+++ b/tap-snapshots/test-nyc-integration.js-TAP.test.js
@@ -103,6 +103,9 @@ All files                        |       0 |        0 |       0 |       0 |
   test.js                        |       0 |        0 |       0 |       0 |                         
  cli/fakebin                     |       0 |      100 |     100 |       0 |                         
   npm-template.js                |       0 |      100 |     100 |       0 | 2,3,4,7,9               
+ cli/instrument-inplace          |       0 |      100 |       0 |       0 |                         
+  file1.js                       |       0 |      100 |       0 |       0 | 2,5                     
+  file2.js                       |       0 |      100 |       0 |       0 | 2,5                     
  cli/nyc-config-js               |       0 |        0 |     100 |       0 |                         
   ignore.js                      |       0 |      100 |     100 |       0 | 1                       
   index.js                       |       0 |        0 |     100 |       0 | 1,3,5,7,8,9,10          
@@ -126,7 +129,7 @@ exports[`test/nyc-integration.js TAP --ignore-class-method skips methods that ma
 ---------------------------------|---------|----------|---------|---------|-------------------------
 File                             | % Stmts | % Branch | % Funcs | % Lines | Uncovered Line #s       
 ---------------------------------|---------|----------|---------|---------|-------------------------
-All files                        |    1.49 |        0 |    5.56 |    1.96 |                         
+All files                        |    1.45 |        0 |       5 |    1.89 |                         
  cli                             |    2.08 |        0 |    5.56 |    3.13 |                         
   args.js                        |       0 |      100 |     100 |       0 | 1                       
   by-arg2.js                     |       0 |        0 |     100 |       0 | 1,2,3,4,5,7             
@@ -144,6 +147,9 @@ All files                        |    1.49 |        0 |    5.56 |    1.96 |
   skip-full.js                   |       0 |      100 |     100 |       0 | 1,2                     
  cli/fakebin                     |       0 |      100 |     100 |       0 |                         
   npm-template.js                |       0 |      100 |     100 |       0 | 2,3,4,7,9               
+ cli/instrument-inplace          |       0 |      100 |       0 |       0 |                         
+  file1.js                       |       0 |      100 |       0 |       0 | 2,5                     
+  file2.js                       |       0 |      100 |       0 |       0 | 2,5                     
  cli/nyc-config-js               |       0 |        0 |     100 |       0 |                         
   ignore.js                      |       0 |      100 |     100 |       0 | 1                       
   index.js                       |       0 |        0 |     100 |       0 | 1,3,5,7,8,9,10          
diff --git a/test/fixtures/cli/instrument-inplace/file1.js b/test/fixtures/cli/instrument-inplace/file1.js
new file mode 100644
index 000000000..d8c7ef465
--- /dev/null
+++ b/test/fixtures/cli/instrument-inplace/file1.js
@@ -0,0 +1,5 @@
+function test() {
+  return 'file1'
+}
+
+module.exports = test
diff --git a/test/fixtures/cli/instrument-inplace/file2.js b/test/fixtures/cli/instrument-inplace/file2.js
new file mode 100644
index 000000000..5ca85a3f0
--- /dev/null
+++ b/test/fixtures/cli/instrument-inplace/file2.js
@@ -0,0 +1,5 @@
+function test() {
+	return 'file2'
+}
+
+module.exports = test
diff --git a/test/nyc-integration-old.js b/test/nyc-integration-old.js
index 6190dc005..40041876f 100644
--- a/test/nyc-integration-old.js
+++ b/test/nyc-integration-old.js
@@ -7,6 +7,7 @@ const fixturesCLI = path.resolve(__dirname, './fixtures/cli')
 const fakebin = path.resolve(fixturesCLI, 'fakebin')
 const fs = require('fs')
 const isWindows = require('is-windows')()
+const cpFile = require('cp-file')
 const rimraf = require('rimraf')
 const makeDir = require('make-dir')
 const { spawn } = require('child_process')
@@ -325,7 +326,7 @@ describe('the nyc cli', function () {
       })
 
       it('aborts if trying to write files in place', function (done) {
-        const args = [bin, 'instrument', '--delete', './', './']
+        const args = [bin, 'instrument', './', './']
 
         const proc = spawn(process.execPath, args, {
           cwd: fixturesCLI,
@@ -339,7 +340,54 @@ describe('the nyc cli', function () {
 
         proc.on('close', function (code) {
           code.should.equal(1)
-          stderr.should.include('nyc instrument failed: cannot instrument files in place')
+          stderr.should.include('cannot instrument files in place')
+          done()
+        })
+      })
+
+      it('can write files in place with --in-place switch', function (done) {
+        const args = [bin, 'instrument', '--in-place', '--include', '*/file1.js', './test-instrument-inplace']
+
+        const sourceDir = path.resolve(fixturesCLI, 'instrument-inplace')
+        const destDir = path.resolve(fixturesCLI, 'test-instrument-inplace')
+        makeDir.sync(destDir)
+        cpFile.sync(path.join(sourceDir, 'file1.js'), path.join(destDir, 'file1.js'))
+        cpFile.sync(path.join(sourceDir, 'file2.js'), path.join(destDir, 'file2.js'))
+
+        const proc = spawn(process.execPath, args, {
+          cwd: fixturesCLI,
+          env: env
+        })
+
+        proc.on('close', function (code) {
+          code.should.equal(0)
+          const file1 = path.resolve(destDir, 'file1.js')
+          fs.readFileSync(file1, 'utf8')
+            .should.match(/var cov_/)
+          const file2 = path.resolve(destDir, 'file2.js')
+          fs.readFileSync(file2, 'utf8')
+            .should.not.match(/var cov_/)
+          rimraf.sync(destDir)
+          done()
+        })
+      })
+
+      it('aborts if trying to delete while writing files in place', function (done) {
+        const args = [bin, 'instrument', '--in-place', '--delete', '--include', 'file1.js', './instrument-inplace']
+
+        const proc = spawn(process.execPath, args, {
+          cwd: fixturesCLI,
+          env: env
+        })
+
+        let stderr = ''
+        proc.stderr.on('data', function (chunk) {
+          stderr += chunk
+        })
+
+        proc.on('close', function (code) {
+          code.should.equal(1)
+          stderr.should.include(`cannot use '--delete' when instrumenting files in place`)
           done()
         })
       })
@@ -359,7 +407,7 @@ describe('the nyc cli', function () {
 
         proc.on('close', function (code) {
           code.should.equal(1)
-          stderr.should.include('nyc instrument failed: cannot instrument files outside of project root directory')
+          stderr.should.include('cannot instrument files outside project root directory')
           done()
         })
       })
@@ -421,7 +469,7 @@ describe('the nyc cli', function () {
 
           proc.on('close', function (code) {
             code.should.equal(1)
-            stderr.should.include('nyc instrument failed: attempt to delete')
+            stderr.should.include('attempt to delete')
             done()
           })
         })
@@ -441,7 +489,7 @@ describe('the nyc cli', function () {
 
           proc.on('close', function (code) {
             code.should.equal(1)
-            stderr.should.include('nyc instrument failed: attempt to delete')
+            stderr.should.include('attempt to delete')
             done()
           })
         })