MitsunChieh

sudo rm -rf /Applications/Xcode.app
sudo rm -rf /Library/Preferences/com.apple.dt.Xcode.plist

rm -rf ~/Library/Preferences/com.apple.dt.Xcode.plist
rm -rf ~/Library/Caches/com.apple.dt.Xcode
rm -rf ~/Library/Application\ Support/Xcode

rm -rf ~/Library/Developer/Xcode
rm -rf ~/Library/Developer/CoreSimulator
rm -rf ~/Library/Developer/XCPGDevices

MitsunChieh

# Additional translations at https://github.com/plataformatec/devise/wiki/I18n

zh-TW:
  devise:
    confirmations:
      confirmed: "您的帳號已通過驗證，現在您已成功登入。"
      send_instructions: "您將在幾分鐘後收到一封電子郵件，內有驗證帳號的步驟說明。"
      send_paranoid_instructions: "如果我們有您的信箱，您將會收到一封驗證您的帳號的電子郵件。"
    failure:
      already_authenticated: "您已經登入。"

MitsunChieh

# Additional translations at https://github.com/plataformatec/devise/wiki/I18n

zh-TW:
  devise:
    confirmations:
      confirmed: "您的帳號已通過驗證，現在您已成功登入。"
      send_instructions: "您將在幾分鐘後收到一封電子郵件，內有驗證帳號的步驟說明。"
      send_paranoid_instructions: "如果我們有您的信箱，您將會收到一封驗證您的帳號的電子郵件。"
    failure:
      already_authenticated: "您已經登入。"

MitsunChieh

# 資料庫備份
mysqldump -u[user] -p -P[port] -h[host] db_name > back_up.sql

# 資料庫備份，但排除特定資料表
mysqldump -u[user] -p -P[port] -h[host] db_name --ignore-table=db_name.table_name > back_up.sql

# 壓縮成 tgz
tar zcf filename.tgz filename1 filename2

# 解壓縮從 tgz

MitsunChieh

# 09azAZ
# n = 字串的長度
range = [*0..9,*'a'..'z',*'A'..'Z'];Array.new(n){ range.sample }.join

# 09az
# 長度 128
rake secret

# 好玩的寫法
# 09az

MitsunChieh

foobar = foo.presence || bar
=== foobar = (foo if foo.present?) || bar

結果上來說跟下述等價。

foobar = foo
foobar = bar if foobar.blank?

MitsunChieh

db:create creates the database for the current env

db:create:all creates the databases for all envs

db:drop drops the database for the current env

db:drop:all drops the databases for all envs

db:migrate runs migrations for the current env that have not run yet

MitsunChieh

Just find out some problem in assigning array.

arr3 = Array.new(2, Array.new(2, 0))
arr4 = [[0, 0], [0, 0]]

puts arr3 == arr4	 # >> true
puts arr3 === arr4  # >> true

arr3[0][0] = "/"
print arr3 # >> [["/", 0], ["/", 0]]

MitsunChieh

# Benchmark 是一個記錄程式運算時間的 Module 
# 兩個基本指令 :measure, :bm, :bmbm
# 更多：http://www.ruby-doc.org/stdlib-2.0/libdoc/benchmark/rdoc/Benchmark.html#method-c-measure

require 'benchmark'

puts Benchmark.measure{ method_name } 
#     user     system      total        real   <- 不會有這一行
# 1.033333   0.016667   1.016667 (  0.492106)