Re-enable Windows XP update by applying a registry patch








  • Save the following text:
    Windows Registry Editor Version 5.00
    [HKEY_LOCAL_MACHINESYSTEMWPAPosReady]
    "Installed"=dword:00000001
    
    into a text file named xp.reg
  • double click the reg file to apply the patch.



Java: string.format() align left








String.format("%-20s", "test");



Java: convert int to unsigned








int toUnsigned(short i){
    return Short.toUnsignedInt(); // i&0xffff;
}

long toUnsigned(int i){
    return Integer.toUnsignedLong(); // i&0xffffffffl;
}



Java: Regular expression to match dot separated numbers








The dot separated values look like below:
1
1.2.3
1.2.3.4.5
The regular expression to match: "^\\d+(\\d*.)*\\d+$"

Java code:
System.out.println(Pattern.matches("^\\d+(\\d*.)*\\d+$", "1")); // true
System.out.println(Pattern.matches("^\\d+(\\d*.)*\\d+$", "1.2.3")); // true
System.out.println(Pattern.matches("^\\d+(\\d*.)*\\d+$", "1.2.a")); // false
System.out.println(Pattern.matches("^\\d+(\\d*.)*\\d+$", "1.2.3.")); // false



Java: Check if a year is leap year








public static boolean isLeapYear(int year) {
    assert year >= 1583; // not valid before this date.
    return ((year % 4 == 0) && (year % 100 != 0)) || (year % 400 == 0);
}
public static boolean isLeapYear(int year) {
    Calendar cal = Calendar.getInstance();
    cal.set(Calendar.YEAR, year);
    return cal.getActualMaximum(DAY_OF_YEAR) > 365;
}



Bash: for loop








#!/bin/bash

# backup IFS
IFSBAK=$IFS
IFS=$(echo -en "\n\b")

for f in $(ls)
do
    echo "$f"
done

# restore IFS
IFS=$IFSBAK



几个标点符号的英文翻译








小括号( ) parentheses
中括号[ ] square brackets
大括号{ } curly brackets
尖括号< > angle brackets
: colon
, comma
- hyphen
- - - dash
! Exclamation mark
; semicolon
/ slash
? question mark
. full stop/period


Github: fork a repository and sync the fork








  1. Fork a repository
    • Clone the repository:
      git clone https://github.com/ORIGINAL_OWNER/ORIGINAL_REPO.git
    • Add the original repository as upstream:
      git remote add upstream https://github.com/ORIGINAL_OWNER/ORIGINAL_REPO.git
    • Check the status:
      git remote -v
      You will see:
      # origin    https://github.com/YOUR_USERNAME/YOUR_FORK.git (fetch)
      # origin    https://github.com/YOUR_USERNAME/YOUR_FORK.git (push)
      # upstream  https://github.com/ORIGINAL_OWNER/ORIGINAL_REPO.git (fetch)
      # upstream  https://github.com/ORIGINAL_OWNER/ORIGINAL_REPO.git (push)
      
  2. Sync the fork with upstream(original):
    • Fetch the branches and their respective commits from the upstream repository:
      git fetch upstream
    • Check out your fork's local master branch:
      git checkout master
    • Merge the changes from upstream/master into your local master branch. This brings your fork's master branch into sync with the upstream repository, without losing your local changes.
      git merge upstream/master
    • Push local repository:
      git push --tags