diff --git a/lib/cli-run.js b/lib/cli-run.js
new file mode 100644
index 0000000..5fe0ae9
--- /dev/null
+++ b/lib/cli-run.js
@@ -0,0 +1,5 @@
+#!/usr/bin/env node
+
+const { main } = require('./cli');
+
+process.exit(main());
diff --git a/lib/cli.js b/lib/cli.js
new file mode 100644
index 0000000..3ea12be
--- /dev/null
+++ b/lib/cli.js
@@ -0,0 +1,102 @@
+const fs = require('fs');
+const parseConflictJSON = require('.');
+const { isDiff } = parseConflictJSON;
+const { version, description } = require('../package.json');
+
+
+const help = `\
+usage: npx parse-conflict-json [OPTIONS...] [--] [FILE]...
+
+Parse JSON file(s) and resolve merge conflicts if possible.
+
+options:
+ -h, --help       print this help and exit
+ -v, --version    print version number and exit
+ -i, --in-place   write resolved conflicts back to FILE (default to stdout)
+ -p, --prefer {ours|theirs}
+                  prefer *our* or *their* version of the file, respectively
+                  (default: 'ours')
+
+Exits 0 on success, 1 on error.\
+`;
+
+
+function parseArgs(argv = process.argv.slice(2)) {
+  const argSepIdx = argv.findIndex(x => x == '--');
+  const opts = argSepIdx >= 0 ? argv.slice(0, argSepIdx) : argv;
+  const args = argSepIdx >= 0 ? argv.slice(argSepIdx + 1) : [];
+
+  if (opts.find(arg => arg === "-h" || arg === "--help")) {
+    console.log(help);
+    return;
+  }
+
+  const options = {
+    inPlace: false,
+    prefer: '',
+    files: (args.slice() || []),
+  };
+
+	for (let i = 0, len = opts.length; i < len; i++) {
+    const [opt, ...maybeArg] = opts[i].split('=', 1);
+    switch (opt) {
+      case '-v':
+      case '--version':
+        console.log(version);
+        return;
+      case '-i':
+      case '--in-place':
+        if (maybeArg.length) {
+          throw new Error(`option ${opt} does not take an argument`);
+        }
+        options.inPlace = true;
+      case '-p':
+      case '--prefer':
+        const arg = maybeArg.length ? maybeArg[0] : opts[++i];
+        options.prefer = arg; // error will be thrown by index.js
+      default:
+        if (args.length || opt.startsWith('-')) {
+          throw new Error(`unrecognized option ${opt}`)
+        } else {
+          options.files.push(opt);
+        }
+    }
+  }
+
+  return options;
+}
+
+function main(argv = process.argv.slice(2)) {
+  try {
+    const options = parseArgs(argv);
+    if (!options) { return 0; }
+
+    if (!options.files.length) {
+      throw Error("No files specified!");
+    }
+
+    for (const file of options.files) {
+      const contents = fs.readFileSync(file).toString();
+
+      if (!isDiff(contents)) {
+        console.error(`warning: file {file} does not have conflict markers`);
+      }
+
+      const resolved = parseConflictJSON(contents, null, options.prefer);
+
+      if (options.inPlace) {
+        fs.writeFileSync(file, resolved);
+        console.error(`${file}: wrote ${Buffer.byteLength(resolved, 'utf8')} bytes`)
+      } else {
+        console.log(resolved);
+      }
+    }
+    return 0;
+
+  } catch (err) {
+    console.error(`${err}`);
+    return 1;
+  }
+}
+
+module.exports = { main, parseArgs };
diff --git a/package.json b/package.json
index fc223b6..434b4dc 100644
--- a/package.json
+++ b/package.json
@@ -5,6 +5,7 @@
   "author": "GitHub Inc.",
   "license": "ISC",
   "main": "lib",
+  "bin": "lib/cli-run.js",
   "scripts": {
     "test": "tap",
     "snap": "tap",
@@ -14,17 +15,10 @@
     "posttest": "npm run lint",
     "template-oss-apply": "template-oss-apply --force"
   },
-  "tap": {
-    "check-coverage": true,
-    "nyc-arg": [
-      "--exclude",
-      "tap-snapshots/**"
-    ]
-  },
   "devDependencies": {
     "@npmcli/eslint-config": "^4.0.0",
     "@npmcli/template-oss": "4.21.4",
-    "tap": "^16.0.1"
+    "tap": "^18.7.2"
   },
   "dependencies": {
     "json-parse-even-better-errors": "^3.0.0",
diff --git a/tap-snapshots/test/basic.js.test.cjs b/tap-snapshots/test/basic.js.test.cjs
index 7517f72..1021d04 100644
--- a/tap-snapshots/test/basic.js.test.cjs
+++ b/tap-snapshots/test/basic.js.test.cjs
@@ -5,13 +5,15 @@
  * Make sure to inspect the output below.  Do not ignore changes!
  */
 'use strict'
-exports[`test/basic.js TAP basic usage > parse unconflicted 1`] = `
+exports[`test/basic.js > TAP > basic usage > parse unconflicted 1`] = `
 Object {
   "a": "apple",
+  [Symbol.for(indent)]: "",
+  [Symbol.for(newline)]: "",
 }
 `
 
-exports[`test/basic.js TAP conflicted > parse conflicted, preferring theirs 1`] = `
+exports[`test/basic.js > TAP > conflicted > parse conflicted, preferring theirs 1`] = `
 Object {
   "a": Object {
     "b": Object {
@@ -32,10 +34,12 @@ Object {
     },
     1,
   ],
+  [Symbol.for(indent)]: "",
+  [Symbol.for(newline)]: "",
 }
 `
 
-exports[`test/basic.js TAP conflicted > prefer theirs 1`] = `
+exports[`test/basic.js > TAP > conflicted > prefer theirs 1`] = `
 Object {
   "a": Object {
     "b": Object {
@@ -54,10 +58,12 @@ Object {
     },
     1,
   ],
+  [Symbol.for(indent)]: "",
+  [Symbol.for(newline)]: "",
 }
 `
 
-exports[`test/basic.js TAP error states > BOM is no problem 1`] = `
+exports[`test/basic.js > TAP > error states > BOM is no problem 1`] = `
 Object {
   "a": Object {
     "b": Object {
@@ -78,13 +84,17 @@ Object {
     },
     1,
   ],
+  [Symbol.for(indent)]: "",
+  [Symbol.for(newline)]: "",
 }
 `
 
-exports[`test/basic.js TAP global object attributes > filters out global object attributes 1`] = `
+exports[`test/basic.js > TAP > global object attributes > filters out global object attributes 1`] = `
 Object {
   "__proto__": "__proto__",
   "constructor": "constructor",
+  [Symbol.for(indent)]: "",
+  [Symbol.for(newline)]: "",
   "toString": "toString",
   "x": Object {},
 }
diff --git a/tap-snapshots/test/cli.js.test.cjs b/tap-snapshots/test/cli.js.test.cjs
new file mode 100644
index 0000000..a62075c
--- /dev/null
+++ b/tap-snapshots/test/cli.js.test.cjs
@@ -0,0 +1,438 @@
+/* IMPORTANT
+ * This snapshot file is auto-generated, but designed for humans.
+ * It should be checked into source control and tracked carefully.
+ * Re-generate by setting TAP_SNAPSHOT=1 and running tests.
+ * Make sure to inspect the output below.  Do not ignore changes!
+ */
+'use strict'
+exports[`test/cli.js > TAP > --help arg > exit code 1`] = `
+0
+`
+
+exports[`test/cli.js > TAP > --help arg > stderr 1`] = `
+Array []
+`
+
+exports[`test/cli.js > TAP > --help arg > stdout 1`] = `
+Array [
+  Array [
+    String(
+      usage: npx parse-conflict-json [OPTIONS...] [--] [FILE]...
+      
+      Parse JSON file(s) and resolve merge conflicts if possible.
+      
+      options:
+       -h, --help       print this help and exit
+       -v, --version    print version number and exit
+       -i, --in-place   write resolved conflicts back to FILE (default to stdout)
+       -p, --prefer {ours|theirs}
+                        prefer *our* or *their* version of the file, respectively
+                        (default: 'ours')
+      
+      Exits 0 on success, 1 on error.
+    ),
+  ],
+]
+`
+
+exports[`test/cli.js > TAP > --help arg after other stuff > exit code 1`] = `
+0
+`
+
+exports[`test/cli.js > TAP > --help arg after other stuff > stderr 1`] = `
+Array []
+`
+
+exports[`test/cli.js > TAP > --help arg after other stuff > stdout 1`] = `
+Array [
+  Array [
+    String(
+      usage: npx parse-conflict-json [OPTIONS...] [--] [FILE]...
+      
+      Parse JSON file(s) and resolve merge conflicts if possible.
+      
+      options:
+       -h, --help       print this help and exit
+       -v, --version    print version number and exit
+       -i, --in-place   write resolved conflicts back to FILE (default to stdout)
+       -p, --prefer {ours|theirs}
+                        prefer *our* or *their* version of the file, respectively
+                        (default: 'ours')
+      
+      Exits 0 on success, 1 on error.
+    ),
+  ],
+]
+`
+
+exports[`test/cli.js > TAP > --version arg > exit code 1`] = `
+0
+`
+
+exports[`test/cli.js > TAP > --version arg > stderr 1`] = `
+Array []
+`
+
+exports[`test/cli.js > TAP > --version arg > stdout 1`] = `
+Array [
+  Array [
+    "{VERSION}",
+  ],
+]
+`
+
+exports[`test/cli.js > TAP > -h arg > exit code 1`] = `
+0
+`
+
+exports[`test/cli.js > TAP > -h arg > stderr 1`] = `
+Array []
+`
+
+exports[`test/cli.js > TAP > -h arg > stdout 1`] = `
+Array [
+  Array [
+    String(
+      usage: npx parse-conflict-json [OPTIONS...] [--] [FILE]...
+      
+      Parse JSON file(s) and resolve merge conflicts if possible.
+      
+      options:
+       -h, --help       print this help and exit
+       -v, --version    print version number and exit
+       -i, --in-place   write resolved conflicts back to FILE (default to stdout)
+       -p, --prefer {ours|theirs}
+                        prefer *our* or *their* version of the file, respectively
+                        (default: 'ours')
+      
+      Exits 0 on success, 1 on error.
+    ),
+  ],
+]
+`
+
+exports[`test/cli.js > TAP > -v arg > exit code 1`] = `
+0
+`
+
+exports[`test/cli.js > TAP > -v arg > stderr 1`] = `
+Array []
+`
+
+exports[`test/cli.js > TAP > -v arg > stdout 1`] = `
+Array [
+  Array [
+    "{VERSION}",
+  ],
+]
+`
+
+exports[`test/cli.js > TAP > conflicting file (ours) > exit code 1`] = `
+1
+`
+
+exports[`test/cli.js > TAP > conflicting file (ours) > stderr 1`] = `
+Array [
+  Array [
+    "Error: unrecognized option --prefer",
+  ],
+]
+`
+
+exports[`test/cli.js > TAP > conflicting file (ours) > stdout 1`] = `
+Array []
+`
+
+exports[`test/cli.js > TAP > conflicting file (theirs, arg last) > exit code 1`] = `
+1
+`
+
+exports[`test/cli.js > TAP > conflicting file (theirs, arg last) > stderr 1`] = `
+Array [
+  Array [
+    "Error: unrecognized option --prefer",
+  ],
+]
+`
+
+exports[`test/cli.js > TAP > conflicting file (theirs, arg last) > stdout 1`] = `
+Array []
+`
+
+exports[`test/cli.js > TAP > conflicting file (theirs, arg separate) > exit code 1`] = `
+1
+`
+
+exports[`test/cli.js > TAP > conflicting file (theirs, arg separate) > stderr 1`] = `
+Array [
+  Array [
+    "Error: unrecognized option --prefer",
+  ],
+]
+`
+
+exports[`test/cli.js > TAP > conflicting file (theirs, arg separate) > stdout 1`] = `
+Array []
+`
+
+exports[`test/cli.js > TAP > conflicting file (theirs) > exit code 1`] = `
+1
+`
+
+exports[`test/cli.js > TAP > conflicting file (theirs) > stderr 1`] = `
+Array [
+  Array [
+    "Error: unrecognized option --prefer",
+  ],
+]
+`
+
+exports[`test/cli.js > TAP > conflicting file (theirs) > stdout 1`] = `
+Array []
+`
+
+exports[`test/cli.js > TAP > conflicting file > exit code 1`] = `
+0
+`
+
+exports[`test/cli.js > TAP > conflicting file > stderr 1`] = `
+Array []
+`
+
+exports[`test/cli.js > TAP > conflicting file > stdout 1`] = `
+Array [
+  Array [
+    Object {
+      "a": Object {
+        "b": Object {
+          "c": Object {
+            "x": "bbbb",
+          },
+        },
+      },
+      "array": Array [
+        100,
+        Object {
+          "foo": "baz",
+        },
+        1,
+        3,
+        Object {
+          "foo": "bar",
+        },
+        1,
+      ],
+      [Symbol.for(indent)]: "",
+      [Symbol.for(newline)]: "",
+    },
+  ],
+]
+`
+
+exports[`test/cli.js > TAP > in-place updates > exit code 1`] = `
+1
+`
+
+exports[`test/cli.js > TAP > in-place updates > file broken.json 1`] = `
+{
+  "array": [
+<<<<<<< HEAD
+    100,
+    {
+      "foo": "baz",
+    },
+||||||| merged common ancestors
+    1,
+=======
+    111,
+    1,
+    2,
+    3,
+    {
+      "foo": "bar"
+    },
+>>>>>>> a
+    1
+  ],
+  "a": {
+    "b": {
+<<<<<<< HEAD
+      "c": {
+        "x": "bbbb"
+      }
+||||||| merged common ancestors
+      "c": {
+        "x": "aaaa"
+      }
+=======
+      "c": "xxxx"
+>>>>>>> a
+    }
+  }
+}
+
+`
+
+exports[`test/cli.js > TAP > in-place updates > file conflicted.json 1`] = `
+{
+  "array": [
+<<<<<<< HEAD
+    100,
+    {
+      "foo": "baz"
+    },
+||||||| merged common ancestors
+    1,
+=======
+    111,
+    1,
+    2,
+    3,
+    {
+      "foo": "bar"
+    },
+>>>>>>> a
+    1
+  ],
+  "a": {
+    "b": {
+<<<<<<< HEAD
+      "c": {
+        "x": "bbbb"
+      }
+||||||| merged common ancestors
+      "c": {
+        "x": "aaaa"
+      }
+=======
+      "c": "xxxx"
+>>>>>>> a
+    }
+  }
+}
+
+`
+
+exports[`test/cli.js > TAP > in-place updates > file proto.json 1`] = `
+{
+  "constructor": "constructor",
+  "toString": "toString",
+  "__proto__": "__proto__",
+  "x": {
+<<<<<<<
+    "__proto__": {
+      "foo": "__proto__.foo"
+    }
+=======
+>>>>>>>
+  }
+}
+
+`
+
+exports[`test/cli.js > TAP > in-place updates > stderr 1`] = `
+Array [
+  Array [
+    "Error: unrecognized option --in-place",
+  ],
+]
+`
+
+exports[`test/cli.js > TAP > in-place updates > stdout 1`] = `
+Array []
+`
+
+exports[`test/cli.js > TAP > multiple files > exit code 1`] = `
+0
+`
+
+exports[`test/cli.js > TAP > multiple files > stderr 1`] = `
+Array []
+`
+
+exports[`test/cli.js > TAP > multiple files > stdout 1`] = `
+Array [
+  Array [
+    Object {
+      "a": Object {
+        "b": Object {
+          "c": Object {
+            "x": "bbbb",
+          },
+        },
+      },
+      "array": Array [
+        100,
+        Object {
+          "foo": "baz",
+        },
+        1,
+        3,
+        Object {
+          "foo": "bar",
+        },
+        1,
+      ],
+      [Symbol.for(indent)]: "",
+      [Symbol.for(newline)]: "",
+    },
+  ],
+  Array [
+    Object {
+      "a": Object {
+        "b": Object {
+          "c": Object {
+            "x": "bbbb",
+          },
+        },
+      },
+      "array": Array [
+        100,
+        Object {
+          "foo": "baz",
+        },
+        1,
+        3,
+        Object {
+          "foo": "bar",
+        },
+        1,
+      ],
+      [Symbol.for(indent)]: "",
+      [Symbol.for(newline)]: "",
+    },
+  ],
+]
+`
+
+exports[`test/cli.js > TAP > no args > exit code 1`] = `
+1
+`
+
+exports[`test/cli.js > TAP > no args > stderr 1`] = `
+Array [
+  Array [
+    "Error: No files specified!",
+  ],
+]
+`
+
+exports[`test/cli.js > TAP > no args > stdout 1`] = `
+Array []
+`
+
+exports[`test/cli.js > TAP > nonexistent file > exit code 1`] = `
+1
+`
+
+exports[`test/cli.js > TAP > nonexistent file > stderr 1`] = `
+Array [
+  Array [
+    "Error: ENOENT: no such file or directory, open 'nonexistent_file.json'",
+  ],
+]
+`
+
+exports[`test/cli.js > TAP > nonexistent file > stdout 1`] = `
+Array []
+`
diff --git a/test/cli.js b/test/cli.js
new file mode 100644
index 0000000..f571da9
--- /dev/null
+++ b/test/cli.js
@@ -0,0 +1,62 @@
+const cli = require('../lib/cli')
+const { version } = require('../package.json')
+const t = require('tap')
+const { readFileSync } = require('fs')
+
+const path = require('path')
+const conflictedPath = path.join(__dirname, '/fixtures/conflicted.json');
+const brokenPath = path.join(__dirname, '/fixtures/broken.json');
+const protoPath = path.join(__dirname, '/fixtures/prototype.json');
+
+t.cleanSnapshot = s => s.replace(version, '{VERSION}');
+
+t.beforeEach(t => {
+  t.outs = t.capture(console, 'log');
+  t.errs = t.capture(console, 'error');
+});
+
+for (const desc_arg of [
+  ['no args', []],
+  ['-h arg', ['-h']],
+  ['--help arg', ['--help']],
+  ['--help arg after other stuff', ['file1', 'file2', '--prefer', '--help']],
+  ['-v arg', ['-v']],
+  ['--version arg', ['--version']],
+  ['nonexistent file', ['nonexistent_file.json']],
+  ['conflicting file', [conflictedPath]],
+  ['conflicting file (ours)', ['--prefer=ours', conflictedPath]],
+  ['conflicting file (theirs)', ['--prefer=theirs', conflictedPath]],
+  ['conflicting file (theirs, arg last)', [conflictedPath, '--prefer=theirs']],
+  ['conflicting file (theirs, arg separate)', [conflictedPath, '--prefer', 'theirs']],
+  ['multiple files', [conflictedPath, conflictedPath]],
+]) {
+  const [desc, argv] = desc_arg;
+  t.test(desc, async t => {
+    t.matchSnapshot(cli.main(argv), 'exit code');
+    t.matchSnapshot(t.outs().map(({args}) => args), 'stdout');
+    t.matchSnapshot(t.errs().map(({args}) => args), 'stderr');
+  })
+}
+
+t.test('in-place updates', async t => {
+
+  let files = {
+    'broken.json': readFileSync(brokenPath),
+    'conflicted.json': readFileSync(conflictedPath),
+    'proto.json': readFileSync(protoPath),
+  };
+  let filePaths = Object.keys(files).map(f => path.join(t.testdirName, f));
+  t.testdir(files);
+
+  t.matchSnapshot(cli.main(['--in-place', ...filePaths]), 'exit code');
+  t.matchSnapshot(t.outs().map(({args}) => args), 'stdout');
+  t.matchSnapshot(t.errs().map(({args}) => args), 'stderr');
+
+  for (let f of filePaths) {
+    let newContent = readFileSync(f).toString()
+    let oldContent = files[path.basename(f)];
+    t.notSame(newContent, oldContent);
+    t.matchSnapshot(newContent, `file ${path.basename(f)}`);
+  }
+
+});