diff --git a/index.js b/index.js
index a0eee8f..98481b5 100755
--- a/index.js
+++ b/index.js
@@ -2,13 +2,13 @@
 "use strict";
 
 const tmp = require('tmp');
-const shell = require('shelljs');
+const child_process = require('child_process');
 const assert = require('assert');
 const topsort = require('topsort');
 const fs = require('fs');
-const dagre = require('dagre');
 const HashMap = require('hashmap');
 const bigInt = require('big-integer');
+const {promisify} = require('util');
 
 const ltr2bit = {
     '1': 1,
@@ -587,64 +587,15 @@ function yosys_to_simcir_mod(name, mod, portmaps) {
     return mout;
 }
 
-function layout_circuit(circ) {
-    const g = new dagre.graphlib.Graph();
-    const devmap = {};
-    let maxx = 0, maxy = 0;
-
-    g.setGraph({rankdir: 'RL'});
-    g.setDefaultEdgeLabel(function() { return {}; });
-
-    for (const dev of circ.devices) {
-        g.setNode(dev.id, {
-            id: dev.id,
-            width: 32,
-            height: 32
-        });
-        devmap[dev.id] = dev;
-    }
-
-    for (const conn of circ.connectors) {
-        g.setEdge(conn.from.id, conn.to.id);
-    }
-
-    dagre.layout(g);
-
-    for (const nname of g.nodes()) {
-        const node = g.node(nname);
-        devmap[node.id].x = node.x;
-        devmap[node.id].y = node.y;
-        maxx = Math.max(maxx, node.x);
-        maxy = Math.max(maxy, node.y);
-        //console.log(nname + ":" + JSON.stringify(node));
-    }
-
-    circ.width = maxx + 256;
-    circ.height = maxy + 64;
-}
-
-function layout_circuits(circs) {
-    for (const name in circs) {
-        layout_circuit(circs[name]);
-    }
-}
-
-function process(filenames) {
-    const tmpjson = tmp.tmpNameSync({ postfix: '.json' });
-    const yosys_result = shell.exec(
+async function process(filenames) {
+    const tmpjson = await promisify(tmp.tmpName)({ postfix: '.json' });
+    const yosys_result = await promisify(child_process.exec)(
         'yosys -p "hierarchy; proc; fsm; memory -nomap" -o "' + tmpjson + '" ' + filenames.join(' '),
-        {silent: true});
-    if (yosys_result.code !== 0) {
-        return {
-            status: false,
-            yosys_stdout: yosys_result.stdout
-        };
-    }
+        {maxBuffer: 1000000});
     const obj = JSON.parse(fs.readFileSync(tmpjson, 'utf8'));
-    shell.rm(tmpjson);
+    await promisify(fs.unlink)(tmpjson);
     const portmaps = order_ports(obj);
     const out = yosys_to_simcir(obj, portmaps);
-    //layout_circuits(out);
     const toporder = topsort(module_deps(obj));
     toporder.pop();
     const toplevel = toporder.pop();
@@ -660,16 +611,17 @@ function process(filenames) {
     return {
         status: true,
         output: output,
-        yosys_stdout: yosys_result.stdout
+        yosys_stdout: yosys_result.stdout,
+        yosys_stderr: yosys_result.stderr
     };
 }
 
-function process_sv(text) {
-    const tmpsv = tmp.fileSync({ postfix: '.sv' });
-    fs.writeSync(tmpsv.fd, text);
-    fs.closeSync(tmpsv.fd);
-    const ret = process([tmpsv.name]);
-    shell.rm(tmpsv.name);
+async function process_sv(text) {
+    const tmpsv = await promisify(tmp.fileSync)({ postfix: '.sv' });
+    await promisify(fs.writeSync)(tmpsv.fd, text);
+    await promisify(fs.closeSync)(tmpsv.fd);
+    const ret = await process([tmpsv.name]);
+    await promisify(fs.unlink)(tmpsv.name);
     return ret;
 }
 
diff --git a/package-lock.json b/package-lock.json
index d0ec408..22dfd47 100644
--- a/package-lock.json
+++ b/package-lock.json
@@ -4,156 +4,26 @@
   "lockfileVersion": 1,
   "requires": true,
   "dependencies": {
-    "balanced-match": {
-      "version": "1.0.0",
-      "resolved": "https://registry.npmjs.org/balanced-match/-/balanced-match-1.0.0.tgz",
-      "integrity": "sha1-ibTRmasr7kneFk6gK4nORi1xt2c="
-    },
     "big-integer": {
       "version": "1.6.34",
       "resolved": "https://registry.npmjs.org/big-integer/-/big-integer-1.6.34.tgz",
       "integrity": "sha512-+w6B0Uo0ZvTSzDkXjoBCTNK0oe+aVL+yPi7kwGZm8hd8+Nj1AFPoxoq1Bl/mEu/G/ivOkUc1LRqVR0XeWFUzuA=="
     },
-    "brace-expansion": {
-      "version": "1.1.11",
-      "resolved": "https://registry.npmjs.org/brace-expansion/-/brace-expansion-1.1.11.tgz",
-      "integrity": "sha512-iCuPHDFgrHX7H2vEI/5xpz07zSHB00TpugqhmYtVmMO6518mCuRMoOYFldEBl0g187ufozdaHgWKcYFb61qGiA==",
-      "requires": {
-        "balanced-match": "1.0.0",
-        "concat-map": "0.0.1"
-      }
-    },
-    "concat-map": {
-      "version": "0.0.1",
-      "resolved": "https://registry.npmjs.org/concat-map/-/concat-map-0.0.1.tgz",
-      "integrity": "sha1-2Klr13/Wjfd5OnMDajug1UBdR3s="
-    },
-    "dagre": {
-      "version": "0.8.2",
-      "resolved": "https://registry.npmjs.org/dagre/-/dagre-0.8.2.tgz",
-      "integrity": "sha1-dVt59NVJnWPPdMM2j7CK3ZPs6v4=",
-      "requires": {
-        "graphlib": "2.1.5",
-        "lodash": "4.17.10"
-      }
-    },
-    "fs.realpath": {
-      "version": "1.0.0",
-      "resolved": "https://registry.npmjs.org/fs.realpath/-/fs.realpath-1.0.0.tgz",
-      "integrity": "sha1-FQStJSMVjKpA20onh8sBQRmU6k8="
-    },
-    "glob": {
-      "version": "7.1.2",
-      "resolved": "https://registry.npmjs.org/glob/-/glob-7.1.2.tgz",
-      "integrity": "sha512-MJTUg1kjuLeQCJ+ccE4Vpa6kKVXkPYJ2mOCQyUuKLcLQsdrMCpBPUi8qVE6+YuaJkozeA9NusTAw3hLr8Xe5EQ==",
-      "requires": {
-        "fs.realpath": "1.0.0",
-        "inflight": "1.0.6",
-        "inherits": "2.0.3",
-        "minimatch": "3.0.4",
-        "once": "1.4.0",
-        "path-is-absolute": "1.0.1"
-      }
-    },
-    "graphlib": {
-      "version": "2.1.5",
-      "resolved": "https://registry.npmjs.org/graphlib/-/graphlib-2.1.5.tgz",
-      "integrity": "sha1-av4a/MUUhVXseZ5JkFZ5W9aTjIc=",
-      "requires": {
-        "lodash": "4.17.10"
-      }
-    },
     "hashmap": {
       "version": "2.3.0",
       "resolved": "https://registry.npmjs.org/hashmap/-/hashmap-2.3.0.tgz",
       "integrity": "sha1-sT+2XafIul49uPwbjFuh0ASdryI="
     },
-    "inflight": {
-      "version": "1.0.6",
-      "resolved": "https://registry.npmjs.org/inflight/-/inflight-1.0.6.tgz",
-      "integrity": "sha1-Sb1jMdfQLQwJvJEKEHW6gWW1bfk=",
-      "requires": {
-        "once": "1.4.0",
-        "wrappy": "1.0.2"
-      }
-    },
-    "inherits": {
-      "version": "2.0.3",
-      "resolved": "https://registry.npmjs.org/inherits/-/inherits-2.0.3.tgz",
-      "integrity": "sha1-Yzwsg+PaQqUC9SRmAiSA9CCCYd4="
-    },
-    "interpret": {
-      "version": "1.1.0",
-      "resolved": "https://registry.npmjs.org/interpret/-/interpret-1.1.0.tgz",
-      "integrity": "sha1-ftGxQQxqDg94z5XTuEQMY/eLhhQ="
-    },
-    "lodash": {
-      "version": "4.17.10",
-      "resolved": "https://registry.npmjs.org/lodash/-/lodash-4.17.10.tgz",
-      "integrity": "sha1-G3eTz3JZ6jj7NmHU04syYK+K5Oc="
-    },
-    "minimatch": {
-      "version": "3.0.4",
-      "resolved": "https://registry.npmjs.org/minimatch/-/minimatch-3.0.4.tgz",
-      "integrity": "sha512-yJHVQEhyqPLUTgt9B83PXu6W3rx4MvvHvSUvToogpwoGDOUQ+yDrR0HRot+yOCdCO7u4hX3pWft6kWBBcqh0UA==",
-      "requires": {
-        "brace-expansion": "1.1.11"
-      }
-    },
     "minimist": {
       "version": "1.2.0",
       "resolved": "https://registry.npmjs.org/minimist/-/minimist-1.2.0.tgz",
       "integrity": "sha1-o1AIsg9BOD7sH7kU9M1d95omQoQ="
     },
-    "once": {
-      "version": "1.4.0",
-      "resolved": "https://registry.npmjs.org/once/-/once-1.4.0.tgz",
-      "integrity": "sha1-WDsap3WWHUsROsF9nFC6753Xa9E=",
-      "requires": {
-        "wrappy": "1.0.2"
-      }
-    },
     "os-tmpdir": {
       "version": "1.0.2",
       "resolved": "https://registry.npmjs.org/os-tmpdir/-/os-tmpdir-1.0.2.tgz",
       "integrity": "sha1-u+Z0BseaqFxc/sdm/lc0VV36EnQ="
     },
-    "path-is-absolute": {
-      "version": "1.0.1",
-      "resolved": "https://registry.npmjs.org/path-is-absolute/-/path-is-absolute-1.0.1.tgz",
-      "integrity": "sha1-F0uSaHNVNP+8es5r9TpanhtcX18="
-    },
-    "path-parse": {
-      "version": "1.0.6",
-      "resolved": "https://registry.npmjs.org/path-parse/-/path-parse-1.0.6.tgz",
-      "integrity": "sha512-GSmOT2EbHrINBf9SR7CDELwlJ8AENk3Qn7OikK4nFYAu3Ote2+JYNVvkpAEQm3/TLNEJFD/xZJjzyxg3KBWOzw=="
-    },
-    "rechoir": {
-      "version": "0.6.2",
-      "resolved": "https://registry.npmjs.org/rechoir/-/rechoir-0.6.2.tgz",
-      "integrity": "sha1-hSBLVNuoLVdC4oyWdW70OvUOM4Q=",
-      "requires": {
-        "resolve": "1.8.1"
-      }
-    },
-    "resolve": {
-      "version": "1.8.1",
-      "resolved": "https://registry.npmjs.org/resolve/-/resolve-1.8.1.tgz",
-      "integrity": "sha512-AicPrAC7Qu1JxPCZ9ZgCZlY35QgFnNqc+0LtbRNxnVw4TXvjQ72wnuL9JQcEBgXkI9JM8MsT9kaQoHcpCRJOYA==",
-      "requires": {
-        "path-parse": "1.0.6"
-      }
-    },
-    "shelljs": {
-      "version": "0.8.2",
-      "resolved": "https://registry.npmjs.org/shelljs/-/shelljs-0.8.2.tgz",
-      "integrity": "sha512-pRXeNrCA2Wd9itwhvLp5LZQvPJ0wU6bcjaTMywHHGX5XWhVN2nzSu7WV0q+oUY7mGK3mgSkDDzP3MgjqdyIgbQ==",
-      "requires": {
-        "glob": "7.1.2",
-        "interpret": "1.1.0",
-        "rechoir": "0.6.2"
-      }
-    },
     "tmp": {
       "version": "0.0.33",
       "resolved": "https://registry.npmjs.org/tmp/-/tmp-0.0.33.tgz",
@@ -166,11 +36,6 @@
       "version": "0.0.2",
       "resolved": "https://registry.npmjs.org/topsort/-/topsort-0.0.2.tgz",
       "integrity": "sha1-Ll4O6KFDlBfxAdW5stA15iAmMyE="
-    },
-    "wrappy": {
-      "version": "1.0.2",
-      "resolved": "https://registry.npmjs.org/wrappy/-/wrappy-1.0.2.tgz",
-      "integrity": "sha1-tSQ9jz7BqjXxNkYFvA0QNuMKtp8="
     }
   }
 }
diff --git a/package.json b/package.json
index c301149..76a9845 100644
--- a/package.json
+++ b/package.json
@@ -1,6 +1,6 @@
 {
   "name": "yosys2digitaljs",
-  "version": "0.0.1",
+  "version": "0.0.2",
   "description": "Export Yosys netlists to a logic simulator",
   "main": "index.js",
   "scripts": {
@@ -10,10 +10,8 @@
   "license": "BSD-2-Clause",
   "dependencies": {
     "big-integer": "^1.6.34",
-    "dagre": "^0.8.0",
     "hashmap": "^2.3.0",
     "minimist": "^1.2.0",
-    "shelljs": "^0.8.2",
     "tmp": "0.0.33",
     "topsort": "^0.0.2"
   },
diff --git a/process.js b/process.js
index e301299..ac5428a 100755
--- a/process.js
+++ b/process.js
@@ -2,7 +2,6 @@
 "use strict";
 
 const argv = require('minimist')(process.argv.slice(2));
-const shell = require('shelljs');
 
 const header = `<!doctype html>
 <html>
@@ -15,25 +14,27 @@ const header = `<!doctype html>
 
 if (argv._.length === 0) {
     console.error('No Verilog files passed!');
-    shell.exit(1);
+    process.exit(1);
 }
-const res = require('./index.js').process(argv._);
-if (!res.status) {
+require('./index.js').process(argv._)
+.then(res => {
+    if (argv.html) {
+        console.log(header);
+        console.log('<div id="paper"></div><script>const circuit = new digitaljs.Circuit(');
+    };
+    if (argv.yosys_out) {
+        console.log('/*');
+        console.log(res.yosys_stdout);
+        console.log('*/');
+    }
+    console.log(JSON.stringify(res.output, null, 2));
+    if (argv.html) {
+        console.log(');const paper = circuit.displayOn($(\'#paper\'));</script></body></html>');
+    };
+})
+.catch(res => {
     console.error('Yosys failed!');
-    console.error(res.yosys_stdout);
-    shell.exit(1);
-}
-if (argv.html) {
-    console.log(header);
-    console.log('<div id="paper"></div><script>const circuit = new digitaljs.Circuit(');
-};
-if (argv.yosys_out) {
-    console.log('/*');
-    console.log(res.yosys_stdout);
-    console.log('*/');
-}
-console.log(JSON.stringify(res.output, null, 2));
-if (argv.html) {
-    console.log(');const paper = circuit.displayOn($(\'#paper\'));</script></body></html>');
-};
+    console.error(res.stderr);
+    process.exit(1);
+});