Add ln support, including both -s and -f options.

README.md

@@ -439,6 +439,23 @@ Display the list of currently remembered directories. Returns an array of paths
 See also: pushd, popd
 
 
+### ln(options, source, dest)
+### ln(source, dest)
+Available options:
+
++ `s`: symlink
++ `f`: force
+
+Examples:
+
+```javascript
+ln('file', 'newlink');
+ln('-sf', 'file', 'existing');
+```
+
+Links source to dest. Use -f to force the link, should dest already exist.
+
+
 ### exit(code)
 Exits the current process with the given exit code.
 

shell.js

@@ -85,6 +85,10 @@ exports.pushd = common.wrap('pushd', _pushd);
 var _popd = require('./src/dirs').popd;
 exports.popd = common.wrap("popd", _popd);
 
+//@include ./src/ln
+var _ln = require('./src/ln');
+exports.ln = common.wrap('ln', _ln);
+
 //@
 //@ ### exit(code)
 //@ Exits the current process with the given exit code.

src/ln.js

@@ -0,0 +1,52 @@
+var fs = require('fs');
+var path = require('path');
+var common = require('./common');
+
+//@
+//@ ### ln(options, source, dest)
+//@ ### ln(source, dest)
+//@ Available options:
+//@
+//@ + `s`: symlink
+//@ + `f`: force
+//@
+//@ Examples:
+//@
+//@ ```javascript
+//@ ln('file', 'newlink');
+//@ ln('-sf', 'file', 'existing');
+//@ ```
+//@
+//@ Links source to dest. Use -f to force the link, should dest already exist.
+function _ln(options, source, dest) {
+  options = common.parseOptions(options, {
+    's': 'symlink',
+    'f': 'force'
+  });
+
+  if (!source || !dest) {
+    common.error('Missing <source> and/or <dest>');
+  }
+
+  source = path.join(process.cwd(), String(source));
+  dest = path.join(process.cwd(), String(dest));
+
+  if (!fs.existsSync(source)) {
+    common.error('Source file does not exist', true);
+  }
+
+  if (fs.existsSync(dest)) {
+    if (!options.force) {
+      common.error('Destination file exists', true);
+    }
+
+    fs.unlinkSync(dest);
+  }
+
+  if (options.symlink) {
+    fs.symlinkSync(source, dest);
+  } else {
+    fs.linkSync(source, dest);
+  }
+}
+module.exports = _ln;

test/ln.js

@@ -0,0 +1,85 @@
+var shell = require('..');
+
+var assert = require('assert'),
+    fs = require('fs');
+
+shell.config.silent = true;
+
+shell.rm('-rf', 'tmp');
+shell.mkdir('tmp');
+
+// Prepare tmp/
+shell.cp('resources/*', 'tmp');
+
+//
+// Invalids
+//
+
+shell.ln();
+assert.ok(shell.error());
+
+shell.ln('file');
+assert.ok(shell.error());
+
+shell.ln('-f');
+assert.ok(shell.error());
+
+shell.ln('tmp/file1', 'tmp/file2');
+assert.ok(shell.error());
+
+shell.ln('tmp/noexist', 'tmp/linkfile1');
+assert.ok(shell.error());
+
+//
+// Valids
+//
+
+shell.ln('tmp/file1', 'tmp/linkfile1');
+assert(fs.existsSync('tmp/linkfile1'));
+assert.equal(
+  fs.readFileSync('tmp/file1').toString(),
+  fs.readFileSync('tmp/linkfile1').toString()
+);
+fs.writeFileSync('tmp/file1', 'new content 1');
+assert.equal(
+  fs.readFileSync('tmp/linkfile1').toString(),
+  'new content 1'
+);
+
+shell.ln('-s', 'tmp/file2', 'tmp/linkfile2');
+assert(fs.existsSync('tmp/linkfile2'));
+assert.equal(
+  fs.readFileSync('tmp/file2').toString(),
+  fs.readFileSync('tmp/linkfile2').toString()
+);
+fs.writeFileSync('tmp/file2', 'new content 2');
+assert.equal(
+  fs.readFileSync('tmp/linkfile2').toString(),
+  'new content 2'
+);
+
+shell.ln('-f', 'tmp/file1.js', 'tmp/file2.js');
+assert(fs.existsSync('tmp/file2.js'));
+assert.equal(
+  fs.readFileSync('tmp/file1.js').toString(),
+  fs.readFileSync('tmp/file2.js').toString()
+);
+fs.writeFileSync('tmp/file1.js', 'new content js');
+assert.equal(
+  fs.readFileSync('tmp/file2.js').toString(),
+  'new content js'
+);
+
+shell.ln('-sf', 'tmp/file1.txt', 'tmp/file2.txt');
+assert(fs.existsSync('tmp/file2.txt'));
+assert.equal(
+  fs.readFileSync('tmp/file1.txt').toString(),
+  fs.readFileSync('tmp/file2.txt').toString()
+);
+fs.writeFileSync('tmp/file1.txt', 'new content txt');
+assert.equal(
+  fs.readFileSync('tmp/file2.txt').toString(),
+  'new content txt'
+);
+
+shell.exit(123);