Archive for the ‘iTechnology’ Category

Rescue Corrupted Disk / SD Card, etc.

About a year ago, my macbook pro died with a corrupted hard disk. I tried multiple ways, the disk just could not be fixed and was not readable or bootable. I had to replace it with a new hard disk, and I was still considering the possibility to get the files back. I tried an open source recovery tool, and it really helped. The basic method was:
1. Make a bootable USB drive;
2. Reboot the system from the USB drive;
3. Run the tool and recover the corrupted files from the dead disk to another selected place.
This tool worked on the command line, but I could not exactly remember the name so far.

Now, one of my SD Card corrupted. To rescue the lost pictures and videos, I searched online and found a tool named TestDisk & PhotoRec, command line based open source software. It works great. It just brings back my memory about the corrupted hard disk for the macbook pro. I am not sure if they are the same one, but they do work the similar way.

Keep a record here for future reference:


Apply Regular Expression Search in Word

Find and replace text by using regular expressions (Advanced)

Simply find Find and Replace” and select “wildcards”, and then you can apply the regular expressions. And the very basic rules are:

To find Type Example
Any single character ? s?t finds sat and set.
Any string of characters * s*d finds sad and started.
The beginning of a word < <(inter) finds interesting and intercept, but not splintered.
The end of a word > (in)> finds in and within, but not interesting.
One of the specified characters [ ] w[io]n finds win and won.
Any single character in this range [-] [r-t]ight finds right and sight. Ranges must be in ascending order.
Any single character except the characters in the range inside the brackets [!x-z] t[!a-m]ck finds tock and tuck, but not tack or tick.
Exactly n occurrences of the previous character or expression {n} fe{2}d finds feed but not fed.
At least n occurrences of the previous character or expression {n,} fe{1,}d finds fed and feed.
From n to m occurrences of the previous character or expression {n,m} 10{1,3} finds 10, 100, and 1000.
One or more occurrences of the previous character or expression @ lo@t finds lot and loot.

For representing the special symbols above, you can use “\” in front of the symbol to identify it. For example, if we want symbol “*”, we should use “\*” in the regular expression.

Validate Email Address in Google Form

Google Form provides a good function to check the respondents’ answer in accordance with customized guidelines. Here is how to set a regular expression to make sure the respondent fill in a valid email address:

  1. Create a form.
  2. From the Insert menu, select “Text” from the list.
  3. Click Advanced Settings at the bottom of the question.
  4. Select Data validation to show the data validation options.
  5. Select Regular expression, Matches.
  6. Copy “^[a-zA-Z0-9._-]+@[a-zA-Z0-9.-]+\.[a-zA-Z]{2,4}$” to the “Patten” field.
  7. Copy “Invalid email address.” to the “Custom error text” field.
  8. Done.

Now, respondents who enter invalid email address will see an error message “Invalid email address.”


  1. Validate answers in your form.
  2. Apps Script Tutorial: Validation.
Categories: iTechnology

Share: “1 Million Users: What I Learned”

01/29/2013 1 comment

I have tried Jotform for my class. Very neat product. Especially, I enjoyed the function to sync the submitted files to dropbox. This semester I notice some nice improvement of it, and I love the function to link to google spreadsheet. So, it brings a lot of potentials.

Today, the founder Aytekin Tank shared a post: “1 Million Users: What I Learned”. Nice article and congratulations to their team!

Categories: iTechnology

Google Search Tips

Categories: iTechnology

To Students: Simplify / Manage Your Life with Google Calendar

10/18/2012 2 comments

From time to time, some of the students can not show up in classes, miss homework deadlines, scheduled appointments, and even exams. Recently, I found most of the students didn’t use any tool to manage their schedules. They try to keep everything in their mind, and if they forget anything, then they miss it.

I have tried to send out reminders regularly. However, I realize that students should know how to manage their own schedule. Here is a technical tip to help – simply use google calendar and task to put everything in one place.

Here are some tutorial resources:

1. Blog post: simplify/manage your life with google calendar

2. Youtube: Google Calendar and Tasks Tutorial

Categories: iTechnology

Google Site in Teaching: File Security

09/17/2012 2 comments

Using Google Sites in teaching for numbers of years, I was thinking about a feature: to have part of the content accessible to limited group of students. However, google doesn’t allow us to simply set a password for a google site. So, I have tried:

1. Make the site private and share it with students.
Problem: I have to collect all the students’ emails, and the students should have their own google accounts. For each semester, I will have to do the same work again.
So, it’s time consuming and inconvenience.

2. Create an extra google account, and share with students the password.
It’s better. But it is still inconvenience for the students who usually use google account. Definitely, they wouldn’t like to switch the account a lot of times. If google sites support multi-account log in, it will still be a nice solution.

3. Leave the site public but make some password protected files.
I like this solution the best so far. If I want to make some content protected, I can make it a password protected pdf or other type of file, and then upload it to the google site. Thus, students will have to have the password to access the file online or read it offline.