YumaInaura

Bash — split $PATH by colon and for in

for i in $(echo "$PATH" | sed 's/:/ /g'); do echo $i;  done;

• Replace colon to space in $PATH
• Pass to for command space separated $PATH
• for command ( foo roop ) catches that strings as multiple arguments ( so not quote string )
  • So double quotationed string pattern does not work well because for command get in string one argument. ( e.g "$(echo "$PATH" | sed 's/:/ /g')" )

YumaInaura

Ruby on rails — How to change column comment with migration

Migration file

  class AddUsersComments < ActiveRecord::Migration[5.1]
  def up
    change_column :users, :first_name, :string, comment: "This is first name of user"
  end

YumaInaura

Golang — Understanding channel, buffer, blocking, deadlock and happy groutines.

I was so confused to understand behaviior of Golang channels, buffer, blocking, deadlocking and groutines.

I read Go by Example topics.

YumaInaura

Git — Vim insert mode by default with git EDITOR ( e.g. when git commit editing )

git config

~/.gitconfig

[core]

YumaInaura

Vim—Remember gg and G keystroke with Gravity's G image ( move to top and move to bottom )

This.

Small letter gg is light.

Capital letter G is heavy.

YumaInaura

Bash — Get current directory path of now executed script ( without $PWD env )

When execute this script from some work dir

• $ cd /some/work/dir
• $ bash /path/to/script.sh

One line answer

YumaInaura

BigQuery — Nested WITH clause ( WITH is like a Subquery )

Query Example

WITH result AS (
   WITH example AS ( SELECT * FROM `dataset.table` )
   SELECT * FROM example
)

YumaInaura

Zsh — How to create user defined widget and map with bindkey ( For very beginner of zle )

Another titles

• How to add customized event and bind keymap
• The very beginner to zle of zsh keymapping with bindkey

Step. Create function in shell

YumaInaura

Shell — Detect shell kind ( e.g sh or bash or zsh )

Use dollar and zero variable. $0

This technique is for "shell" not "shell script".

Current Shell

$ echo $0

YumaInaura

Zle — Show all widget list ( $ zle -al )

zle widget can be used by zsh command bindkey.

Command

zle -al