tian-im

# if else then in one line
[ $condition ] && echo 'true' || echo 'false'

# if argument empty then
local arg
echo ${arg:-default_value} # => default_value
arg=present
echo ${arg:-default_value} # => present

# if argument not empty then replace the text

tian-im

#!/usr/bin/bash
# under Mac
nslookup -type=mx DOMAIN_NAME

tian-im

-- Applications -> AppleScript Editor

choose color

-- Now, save it as an application (File -> Save As, and set the File Format pop-up to Application)
-- Reference: http://hints.macworld.com/article.php?story=20060408050920158

tian-im

ini_set('display_errors',1);
ini_set('display_startup_errors',1);
error_reporting(-1);

tian-im

burn_iso () {
  if [[ -z $1 ]] || [[ -z $2 ]]; then
    echo 'usage: burn_iso IDENTIFIER PATH_TO_ISO'
    echo 'hint: you could use `diskutil list` to find out the desired identifier.'
    return
  fi

  # @see http://osxdaily.com/2015/06/05/copy-iso-to-usb-drive-mac-os-x-command/
  # 1. find out the identifier using `diskutil list`

tian-im

usb_installer () {
  if [[ -z $1 ]]; then
    echo 'usage: usb_install PATH_TO_VOLUME'
    return
  fi
  sudo /Applications/Install\ OS\ X\ El\ Capitan.app/Contents/Resources/createinstallmedia --volume $1 --applicationpath /Applications/Install\ OS\ X\ El\ Capitan.app/ --nointeraction
}

tian-im

# All data types that ActiveRecord supports
PostgresqlModel.connection.type_map.try do |type_map|
  type_map.instance_variable_get('@mapping').keys.map do |key|
    key.is_a?(String) ? key : nil # others are oid type
  end.compact.uniq
end

# PostgreSQL
# [ "bit", "bool", "box", "bpchar", "bytea", "char", "cidr", "circle", "citext", "date", "float4", "float8", "hstore", 
# "inet", "int2", "int4", "int8", "interval", "json", "jsonb", "line", "lseg", "ltree", "macaddr", "money", "name", "numeric",

tian-im

# Execute the following commands in terminal to see its output:
# $ curl -L -o resume.rb https://gist.github.com/tian-im/510644be3c5453f81bc86c8515d2d48b/raw && gem install rspec -N
# $ rspec resume.rb --format documentation --color

module Resume
  puts <<~CONTACT
    name:       Tianwen "Tian" Chen
    email:      me at tian.im
    github:     https://github.com/tian-im
    linkedin:   http://www.linkedin.com/in/tian-im

tian-im

#!/usr/bin/env bash

source $HOME/.rvm/scripts/rvm || source /etc/profile.d/rvm.sh

rvm use --default --install $1

shift

if (( $# ))
then gem install $@

tian-im

# to add
netsh interface portproxy add v4tov4 listenport=3000 listenaddress=127.0.0.1 connectport=3000 connectaddress=10.0.2.2

# to remove
netsh interface portproxy delete v4tov4 listenport=3000 listenaddress=127.0.0.1