Convert "yarn" executable to a shell script that runs either "node" o…

…r "nodejs"

Also fixes Cygwin.
Closes yarnpkg#1142
Closes yarnpkg#819

bin/yarn

@@ -1,2 +1,27 @@
-#!/usr/bin/env node
-require('./yarn.js');
+#!/bin/sh
+basedir=$(dirname "$(echo "$0" | sed -e 's,\\,/,g')")
+
+case `uname` in
+  *CYGWIN*) basedir=`cygpath -w "$basedir"`;;
+esac
+
+command_exists() {
+  command -v "$1" >/dev/null 2>&1;
+}
+
+if command_exists node; then
+  node "$basedir/yarn.js" "$@"
+  ret=$?
+# Debian and Ubuntu use "nodejs" as the name of the binary, not "node", so we
+# search for that too. See:
+# https://lists.debian.org/debian-devel-announce/2012/07/msg00002.html
+# https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=614907
+elif command_exists nodejs; then
+  nodejs "$basedir/yarn.js" "$@"
+  ret=$?
+else
+  echo 'Yarn requires Node.js 4.0 or higher to be installed.'
+  ret=1
+fi
+
+exit $ret

scripts/build-deb.sh

@@ -4,7 +4,7 @@ set -ex
 
 # Ensure all the tools we need are available
 ensureAvailable() {
-  eval $1 --version >/dev/null || (echo "You need to install $1" && exit 2)
+  command -v "$1" >/dev/null 2>&1 || (echo "You need to install $1" && exit 2)
 }
 ensureAvailable dpkg-deb
 ensureAvailable fpm
@@ -13,7 +13,7 @@ ensureAvailable lintian
 ensureAvailable rpmbuild
 
 PACKAGE_TMPDIR=tmp/debian_pkg
-VERSION=`node dist/bin/yarn --version`
+VERSION=`dist/bin/yarn --version`
 TARBALL_NAME=dist/yarn-v$VERSION.tar.gz
 DEB_PACKAGE_NAME=yarn_$VERSION'_all.deb'
 OUTPUT_DIR=artifacts
@@ -50,11 +50,16 @@ find $PACKAGE_TMPDIR/usr/share/yarn \( -name '*.md' -o  -name '*.md~' -o -name '
 # Assume everything else is junk we don't need
 rm -rf $PACKAGE_TMPDIR/dist
 
-# Currently the "binaries" are JavaScript files that expect to be in the same
-# directory as the libraries, so we can't just copy them directly to /usr/bin.
-# Symlink them instead.
+# Swap out the basedir calculation code with a hard-coded path, as the default
+# way we do this doesn't follow symlinks.
+sed -i 's/basedir\=\$.*/basedir=\/usr\/share\/yarn\/bin/' $PACKAGE_TMPDIR/usr/share/yarn/bin/yarn
+
+# The Yarn executable expects to be in the same directory as the libraries, so
+# we can't just copy it directly to /usr/bin. Symlink them instead.
 mkdir -p $PACKAGE_TMPDIR/usr/bin/
-ln -s ../share/yarn/bin/yarn.js $PACKAGE_TMPDIR/usr/bin/yarn
+ln -s ../share/yarn/bin/yarn $PACKAGE_TMPDIR/usr/bin/yarn
+# Alias as "yarnpkg" too.
+ln -s ../share/yarn/bin/yarn $PACKAGE_TMPDIR/usr/bin/yarnpkg
 
 # Common FPM parameters for all packages we'll build using FPM
 FPM="fpm --input-type dir --chdir $PACKAGE_TMPDIR --name yarn --version $VERSION "`
@@ -70,9 +75,6 @@ mkdir -p $PACKAGE_TMPDIR/DEBIAN
 mkdir -p $PACKAGE_TMPDIR/usr/share/lintian/overrides/
 cp resources/debian/lintian-overrides $PACKAGE_TMPDIR/usr/share/lintian/overrides/yarn
 
-# Debian/Ubuntu call the Node.js binary "nodejs", not "node".
-sed -i 's/env node/env nodejs/' $PACKAGE_TMPDIR/usr/share/yarn/bin/yarn.js
-
 # Replace variables in Debian package control file
 INSTALLED_SIZE=`du -sk $PACKAGE_TMPDIR | cut -f 1`
 sed -e "s/\$VERSION/$VERSION/;s/\$INSTALLED_SIZE/$INSTALLED_SIZE/" < resources/debian/control.in > $PACKAGE_TMPDIR/DEBIAN/control

scripts/build-dist.sh

@@ -17,5 +17,5 @@ npm install --production
 rm -rf node_modules/*/test node_modules/*/dist
 cd ..
 
-tar -cvzf dist/yarn-v`node dist/bin/yarn --version`.tar.gz dist/*
+tar -cvzf dist/yarn-v`dist/bin/yarn --version`.tar.gz dist/*
 shasum -a 256 dist/yarn-*.tar.gz