meteor 命令文件shell 解析

#!/bin/bash

# This is the script that we install somewhere in your $PATH (as "meteor")
# when you run
# $ curl https://install.meteor.com/ | sh
# In fact, all that the curl script does is install this script and run it
# once. It's the only file that we install globally on your system; each user of
# Meteor gets their own personal package and tools repository, called the
# warehouse, in ~/.meteor/. This means that a user can share packages among
# multiple apps and automatically update to new releases without having to have
# permissions to write them to anywhere global.
#
# All this script does is exec ~/.meteor/meteor. But what if you don't have it
# yet? In that case, it downloads a "bootstrap tarball", which contains the
# latest version of the Meteor tools, and plops it down at ~/.meteor. In fact,
# once you've run this once, you don't even really need this script: you can put
# ~/.meteor/ into your PATH, or a symlink to ~/.meteor/meteor into some other
# PATH directory. No special permissions needed!
# 脚本的目的在于运行 ~/.meteor/meteor。它会下载一个包：bootstrap tarball，包含了最新
# 版本的Meteor的工具，存放在~/.meteor文件夹下面。事实上，你只要已经运行过一次，你就可
# 不许要这个脚本：你可以把~/.meteor/路径放到你的PATH目录下面,或者加一个链接到PATH目录
# 下面，不许要额外的权限。
#
# To uninstall Meteor from your system, just delete this shell script, and
# delete your warehouse (~/.meteor/).
# 卸载就直接删除~/.meteor/文件夹就行了。
#
# We'll keep around a copy of this file at
# ~/.meteor/engines/latest/launch-meteor just in case you ever want to find it
# again. And if you put it somewhere that other users on your system can run it,
# then when they run it they'll get their very own warehouse too!
# ~/.meteor/engines/latest/launch-meteor 是这个文件的副本，如果你把这个共享给了其他
# 用，那么他们也会有自己的仓库。

set -e
set -u
set -o pipefail # so curl failure triggers the "set -e"

# 设置两个地址
BOOTSTRAP_URL='https://install-bootstrap.meteor.com/'
METEOR_WAREHOUSE_DIR="${METEOR_WAREHOUSE_DIR:-$HOME/.meteor}"

if [ ! -x "$METEOR_WAREHOUSE_DIR/meteor" ]; then # 测试目录
if [ -e "$METEOR_WAREHOUSE_DIR" ]; then
echo "'$METEOR_WAREHOUSE_DIR' exists, but '$METEOR_WAREHOUSE_DIR/meteor' is not executable." 1>&2
echo 1>&2
echo "Remove it and try again." 1>&2
exit 1
fi # 发现仓库路径 但路径里面出现错误

# Bootstrap .meteor from a tarball. First, figure out our architecture.

UNAME=$(uname)
if [ "$UNAME" != "Linux" -a "$UNAME" != "Darwin" ] ; then
echo "Sorry, this OS is not supported yet." 1>&2
exit 1
fi # 系统是否正确

# If you change this, also change host() in tools/archinfo.js
if [ "$UNAME" = "Darwin" ] ; then # osx 系统
if [ "i386" != "$(uname -p)" -o "1" != "$(sysctl -n hw.cpu64bit_capable 2>/dev/null || echo 0)" ] ; then
# Can't just test uname -m = x86_64, because Snow Leopard can
# return other values.
echo "Only 64-bit Intel processors are supported at this time." 1>&2
exit 1 # osx 一定需要64位
fi
ARCH="x86_64"
elif [ "$UNAME" = "Linux" ] ; then # linux 系统
ARCH="$(uname -m)"
if [ "$ARCH" != "i686" -a "$ARCH" != "x86_64" ] ; then
echo "Unsupported architecture: $ARCH" 1>&2
echo "Meteor only supports i686 and x86_64 for now." 1>&2
exit 1 # 32和64都需要
fi
fi
PLATFORM="${UNAME}_${ARCH}" # 平台字符串

# This returns something like https://warehouse.meteor.com/bootstrap/0.6.1
ROOT_URL="$(curl -s --fail $BOOTSTRAP_URL)" # 判断是否提供
TARBALL_URL="${ROOT_URL}/meteor-bootstrap-${PLATFORM}.tar.gz" # 工具包地址

INSTALL_TMPDIR="$(dirname "$METEOR_WAREHOUSE_DIR")/.meteor-install-tmp" # 安装是的临时目录
rm -rf "$INSTALL_TMPDIR" # 清空安装临时目录
mkdir "$INSTALL_TMPDIR" # 创建目录
if [ -n "$USER" ]; then # 提示
echo "$USER, this is your first time using Meteor!" 1>&2
else
echo "This is your first time using Meteor!" 1>&2
fi
echo "Installing a Meteor distribution in your home directory." 1>&2
curl --progress-bar --fail "$TARBALL_URL" | tar -xzf - -C "$INSTALL_TMPDIR" # 下载工具包并且解压到临时目录里面
# bomb out if it didn't work, eg no net
test -x "${INSTALL_TMPDIR}/.meteor/meteor" # 是否有目录
mv "${INSTALL_TMPDIR}/.meteor" "$METEOR_WAREHOUSE_DIR"
rmdir "${INSTALL_TMPDIR}" # 删除临时文件
# just double-checking :)
test -x "$METEOR_WAREHOUSE_DIR/meteor" # 是否安装好
fi

exec "$METEOR_WAREHOUSE_DIR/meteor" "$@" # 执行