codepedia

def stat(path)
  if File.exist?(path)
    File.stat(path.to_s)
  else
    nil
  end
end

codepedia

The below ,removes anything but ascii characters like:

variant_type.gsub!(/[^0-9A-Za-z.\-]/, '')



sql = "INSERT INTO my_table VALUES(#{rows[i].map{|x| x.inspect}.join(', ')})"

vs
sql = "INSERT INTO my_table VALUES(#{ ary.map{ |i| '"%s"' % i }.join(', ') })" 

codepedia

TODO:
Add these two lines to your ~/.inputrc file:

"\eOC": forward-word
"\eOD": backward-word

and press Ctrl-x Ctrl-r to reread the file to make the changes active in your current session.

You will be able to use Ctrl-Right and Ctrl-Left to move right or left word by word.

codepedia

http://donsnotes.com/tech/charsets/ascii.html

x1F
\x00 =>> null  ...

Control Characters

                    CTRL   (^D means to hold the CTRL key and hit d)
Oct  Dec Char  Hex  Key     Comments
\000   0  NUL  \x00  ^@ \0 (Null byte)

codepedia

#in vim 
echo &encoding

# count lines with grep
za:~ za$ grep -c ".*"  file.txt

 2 for Hexadecimal, you could use hd

echo Hello world | hd

codepedia

Bitwise , beause we operate on bits ..example the number 5 has the binary represenation of 01100001 . Bits can also be translated into 
true or false.where repersenting a number where 1 will be false and 0 will be true.

Given two binary strings, complete the following logic operation:
01101 xor 01101

The answer is : 


01101

codepedia

  <!-- <%= link_to  ' log out ',  destroy_user_session_path, :method => :delete %>
 
  <%= link_to(   
      #want to  read more about this helper ...content_tag  =>> http://apidock.com/rails/ActionView/Helpers/TagHelper/content_tag
      content_tag(
         # adda div or h3 here for "log out"
        :i,
        nil, 
        class: 'fa fa-user-times' 
      ), 

codepedia

# Find out if you are root or not for admin tasks.
(( EUID )) && { echo 'Run this script with root priviliges.'; exit 1; } || echo 'Running as root, starting service...'

find userID:
]$ id -u
44502

#za:~ za$ brew search /*\net*/

#!/bin/sh

codepedia

Print keys and values from hash
The \A and \Z are just like "^" and "$"

my @keys;
while (<>) {
   chomp;         # Or: s/\s+\z//;
   push @keys, $_;
}

codepedia

# returns back what was changed after gitting pull locally. 
git diff HEAD^^ HEAD nmae/of/thefile.rb

FYI , 
# this will show what was last added your local "showing newly added changes"
git diff --color HEAD^ HEAD

# this will do the reverse .. it will show the commit prior to pulling from the remote. 
git diff --color HEAD HEAD^