Note to self – How to Clear the Terminal History on Linux or macOS

Copy from https://www.howtogeek.com/179022/how-to-clear-the-terminal-history-on-linux-or-mac-os-x/ as a note to self

Clear the Current Session's History
Your history can be broke down into two chunks. There's your current sessions' history, and there's your long-term history. Our first command, history -c, deals with the current session.

Clear All of Your Bash History
If you want to remove the entirety of your history, run the following command:
rm ~/.bash_history

Use open ~/.bash_history to view and edit

How to validate Libre Office on Mac

For a peace of mind, spend a minute to validate the downloaded file from internet.

Get information from https://download.documentfoundation.org/libreoffice/stable/7.0.4/mac/x86_64/LibreOffice_7.0.4_MacOS_x86-64.dmg.mirrorlist

File information
Filename: LibreOffice_7.0.4_MacOS_x86-64.dmg
Path: /libreoffice/stable/7.0.4/mac/x86_64/LibreOffice_7.0.4_MacOS_x86-64.dmg
Size: 252M (263941643 bytes)
Last modified: Fri, 11 Dec 2020 23:57:25 GMT (Unix time: 1607731045)
SHA-256 Hash: 0fcd83399609780013aee1acc805d1380434118d459829908aa409f7eb67c4e7
SHA-1 Hash: 443de571dad8e412e8b9e4be52ad5b249cc2627f
MD5 Hash: a36fd3c1d5e8935e4732cbf0f826a821
BitTorrent Information Hash: 636f6abbb3ed784831da6385686b1577538e8a39
PGP signature available

Run this command on MacBook: 
openssl dgst -sha256 LibreOffice_7.0.4_MacOS_x86-64.dmg
SHA256(LibreOffice_7.0.4_MacOS_x86-64.dmg)= 0fcd83399609780013aee1acc805d1380434118d459829908aa409f7eb67c4e7

Compare this SHA256 value against with value got from LibreOffice web site above.

How to validate KeePassXC on Mac

Per https://keepassxc.org/download/#mac

Before installing KeePassXC, you should always verify that your download matches the signature that is published alongside the release package! 

openssl dgst -sha256 KeePassXC-2.6.2-2.dmg

Compare the result with value in KeePassXC-2.6.2-2.dmg.DIGEST downloaded from KeePassXC web site

How to make multiple profiles in Mozilla Firefox

Multiple profiles is not visible as in Microsoft Edge Chromium, according to https://developer.mozilla.org/en-US/docs/Mozilla/Firefox/Multiple_profiles

Enter "about:profiles" to create a new profile or update. 

Validate Downloaded Keepass 2.45 on Windows 10

Ran CertUtil and compare with value on https://keepass.info/integrity.html

C:\>certutil -hashfile KeePass-2.45.zip SHA256
SHA256 hash of KeePass-2.45.zip:
d414db9d411acbafd4e1b5faa8605ad7a28829f1814ce779142ffbd5ca9c3794
CertUtil: -hashfile command completed successfully.

C:\>certutil -hashfile KeePass-2.45-Setup.exe sha256
SHA256 hash of KeePass-2.45-Setup.exe:
9058cc9d44129e8c2c902e21f8678974b789ecd8f9d6add81c98fbeaf9794e23
CertUtil: -hashfile command completed successfully.

Per https://keepass.info/integrity.html:

If you want to verify the integrity of your downloaded file, you can hash the file (for instance with one of the following utilities: Visual Hash Calculator, ReHash, MD5sums) and check whether the computed hash matches the one listed below.

OpenPGP signatures can be verified with the public key.

KeePass-2.45.zip:
MD5: 5E838DA8 5050A5C6 DFABB0D6 57C10025
SHA-1: 7EFDC08F BC69D911 A40D29FC 3CA744D2 763C49DF
SHA-256: D414DB9D411ACBAFD4E1B5FAA8605AD7A28829F1814CE779142FFBD5CA9C3794
Size: 3039842 B
Sig.: [OpenPGP ASC]

KeePass-2.45-Setup.exe:
MD5: 5BAAADAA 21098D63 5BB37782 CD9E6446
SHA-1: 68B0A6E5 042A2524 530156C9 34D47E20 C3BC684A
SHA-256: 9058CC9D44129E8C2C902E21F8678974B789ECD8F9D6ADD81C98FBEAF9794E23
Size: 3171656 B
Sig.: [OpenPGP ASC]

Too old for this

Got an email from technical recruiter. But, I'm too senior for this kind of challenging. Thank, I'm pass. Let young person take this. 

Computer technical interview does not alway right especially to an experience software developer.

My Favorite Password Manager

For security, we need a strong password and difference password for difference place. How can I remember all my passwords? My memory is no longer good. 

Solution is using password manager. KeePass is my favorite password manager. To me, it's the best. It's free. It's open source. It may be more secure than other paid password manager.

In Mac OSX, I used KeePassX but now using KeePassXC. Both ported from KeePass.

Check for Conexant Audio Driver Keylogger

Even you don't have HP computer, to be safe, you should make a quick check to see your computer have Conexant log file: MicTray.log or any file name begin with MicTray

Further reading:

1. Arstechnica: HP laptops covertly log user keystrokes, researchers warn
2. SpiceWork: Keylogger in HP audio driver
3. InfoWord: HP computer owners: Check for the MicTray Conexant keylogger

Cloud Services

Cloud services actually is a new “marketing” name for servers hosting with some new features. Nothing new. Instead you contracted AT&T, Verizon, or other … to host your servers, or lease their equipment depend on your budget, network infrastructure architect (100% servers on premise or 25% servers on premise or 50% servers on premise with the rest of server host somewhere else),  you use AWS, Azure, Google Cloud, …

How to disable HTML5 autoplay in Chrome and Firefox

I don't like many web sites automatic play the video in HTML5. I just slow me down and annoy.

To disable it:

For Google Chrome: No way to do it unless I install the add-on plug-in or extension. I don't like that. So just be patient to wait for Google provide that feature or try Eloston extension

For Mozilla Firefox: Set media.autoplay.enabled to false in about:config (Source: http://superuser.com/questions/670214/how-can-i-disable-html5-content-in-popular-browsers-like-firefox-and-chrome ).

Note: Never, never run or enable Adobe Flash player.

How to disable Adobe Flash in FireFox, Google Chrome, Safari and Internet Explorer

Adobe Flash is a nice product and essential tool to surf the web. However, it have big security issues recently. Many security experts recommend not install it. I cannot get rid of Adobe Flash since sometime I need it. So, I make a change to browser to enable them on demand.

Firefox: Type "about:addons" on address bar or Ctrl-Shift-A to manage Add-ons and set "Shockwave Flash to "Ask to Activate"

Google Chrome: Type "chrome://plugins/" on address bar

Safari: Go to References -> Security -> Click on "Plug-in Settings..." next to "Internet Plug-in" check box.

Internet Explorer: Internet Options -> Program -> "Manage Add-on" button

SoCal Code Camp 2015

Some pictures from Southern California Code Camp in Fullerton last Sunday. This is an event I loved it.

Defensive Programming

 Some Dot Net Tips

Exception Rules

Thank organizers, sponsors, and volunteers. May God bless you all.

My experience with Android Studio

I love to learn or try a new thing everyday. Yesterday, I downloaded Android Studio and installed on both Mac OS/X Lion 10.7  and Ubuntu 13.04 laptop. Here is the screenshot of Android Studio my MacBook Pro.

I'm still figuring out how to fix this error: "emulator: ERROR: unknown skin name 'WXGA720'" when  attempt to load Android Virtual Device without using Eclipse Juno to launch the AVD first.

For Ubuntu 13.04, I must using Oracle Java Development Kit instead of OpenJDK to run Android Studio. With Eclipse IDE, I can use OpenJDK. Here is the screenshot when I make a new Android project imported from my GitHub account:

I also trying to install Android Studio on Microsoft Windows. To save time, you need to read carefully the note on http://developer.android.com/sdk/installing/studio.html

Since this is a preview release, I don't expect much. I hope Google will make Android Studio tool better.

Google's Project Glass

I watched Google's Project Glass video few days ago. It's really interesting. But, I'm feeling overwhelmed if I wear this Google Glasses. No, I will not buy this. I don't want my stress level increase. I don't want my life ruined by technology.

“There’s more to life than increasing its speed.” - Mahatma Gandhi

2012 New Year Resolution

A few years ago, I learned the phrase "It's complicated" from Facebook. I love these words. Life is not simple. Some problems may not be easily to solve. It's complicated.

When your computer had a problem or ran too slow, buying a new computer was not a simple solution. You need to find out where the problem is, why the problem exists and how to fix it. When you ran a report, it took long time to return the result. To make it faster, you can not simply add more memory, or change to a faster CPU. It's complicated. You need to spend time to review your code, review your SQL, and monitor performance. You need to think before you act. You cannot simply solve the issue today by leaving more issues for tomorrow.

Now, as I am getting older, I tell myself: KISS (Keep It Simple, Stupid). Beginning this year, I will try to keep everything in my life and my work as simple as I can. Keep it short.

My New Toy

My new toy is a 13-inch MacBook Pro. It took me a lot of time to think over which Mac (Mac Mini, MacBook Air, 13-inch MacBook Pro, or 15-inch MacBook Pro) would be my next working computer. I needed a new computer with a bigger hard drive, longer battery life, and support Intel Virtual Technology. I also needed to familiarize myself with Mac OS X as more people are using Mac OS and iOS. I would have preferred a 15-inch MacBook Pro but I did not want to overspend on a Mac product. Yes, Apple products are high quality but they are too expensive.

My first impression with my MacBook Pro: I can utilize second band 5GHz wireless network (801.11a / 801.11n). Next, it just had only one or two updates, which took a few minutes to install after I initialized the new computer. My Dell Windows 7 took an hour to update. After a system update, I installed Adobe Flash, Java Development Kit SE, LibreOffice, Android SDK, and Eclipse IDE, and Virtual Box. Last, after learning how to use the Multi-Touch track pad, I really like it.

How about the boot time? It is fast but it still cannot beat Ubuntu 11.10 running on a slower CPU, Intel Pentium Dual-Core 2.3GHz.

Microsoft SQL Server

When someone mentioned about Microsoft SQL Server, we thought about money. How much to pay?  Actually Microsoft offers two free versions: Microsoft SQL 2008 R2 Express Edition and Microsoft SQL Compact Edition (CE) 4.0. Developers can use Microsoft SQL 2008R2 Express Edition or Microsoft SQL CE 4.0 for prototype, development, and testing.

Microsoft SQL CE 4.0 is an embedded SQL server database engine. It can use to build standalone and occasionally connected applications for mobile devices, desktops, and Web clients. The maximum database size is 4GB per file.

Microsoft SQL 2008 R2 Express is a free edition of SQL Server ideal for developing and powering desktop, web and small server applications. It can support up to 10GB, 1 CPU and 1GB RAM.

Other paid Microsoft SQL 2008 R2 editions such as Standard, Enterprise, or Data Center support up to 524PB, more than 1 CPU and 64GB RAM, and much more features.

Reference:
Compare Microsoft SQL Server Editions
VS 2010 SP1 and SQL CE - ScottGu's Blog
Everything SQL Server Compact

How to Take a Screenshot

Microsoft Windows
For any Windows version:

1. Press  (Print Screen) key to capture a screenshot of the entire desktop and places it in the clipboard. To capture only the active window, press both   and keys. 
2. Press V to paste the screenshot into other application like Paint or GIMP or Microsoft Word or LibreOffice Writer. 

Another option for Windows Vista and Windows 7 user: Use Snipping Tool to capture screen shots . It a free utility included in Windows Vista and Windows 7

Ubuntu Linux
Press to take a screenshot and save

iOS
Pressing and holding the Home button and the Sleep/Wake button. The screen will flash and the picture will be stored in PNG format in the "Camera Roll" on the iPhone or in "Saved Photos" on the iPod touch. The screenshot feature is only available with iOS 2.0 and later.

Mac OS X
On Mac OS X, a user can take a screenshot of an entire screen by pressing ⌘ Cmd+⇧ Shift+3, or of a chosen area of the screen by ⌘ Cmd+⇧ Shift+4. This screenshot is saved to the user's desktop, with one PNG file per attached monitor.

Google+

A week ago, Google introduced a new social product called Google+ (Google Plus). From what I read on the web since June 28, it sounded good. Someone said it maybe better than Facebook. Every technology sites I visited talked about Google+. It made me curious.

I did not social much but I love to learn a new thing. I love a new technology. I would like to experience Google Plus by myself. Yesterday, I posted on Twitter, Linkedin, Facebook to ask for the Google+ invitation. Today, I got one.

At first, I like it. It's looking good. At the start, you select the people you know into some pre-define circles: family, friend, acquaintance, following,... I made some extra circles for each group of friend. I thought Google+ is better than Facebook in one thing: the privacy. It seems to me the default settings of Google+ are private. In Facebook, the default settings are public, everyone. To maintain your privacy, you need to change you Facebook setting to private, friend only.

Now, I wonder can Google Plus beat Facebook? Anyone need a Google+ invitation?

Back to Android

After  more than six months away from Android programming, I'm back. During the past few months, I put my personal project: Develop an Android application, on hold in order to take care other high priority projects at work and family matters.

One of my resolution last year was develop a mobile application. It will be a show case of my skills. I'm moving from web applications to mobile applications. I spent a lot of time to read whatever related to Android programming. Reading is not enough. I need to practice and do a real work in order to master in something. Get your feet wet. Get hand-on experience. So, while I'm waiting for my car at dealer, I open my laptop, launch the Eclipse IDE and start programming. I switch back and forth between the Eclipse IDE and Google Chrome browser. Each time, I'm stuck with the code, I search for solution on the web. Developer.Android.com is a huge resource for Android programming.

I hope I will have my app ready to release to Android Marketplace in next few months. Yes, I'm hope. :)