Split a zip file in osx

Say you have a big file and you want to zip it up into a few smaller files, (coz email attachment has size limit), here is how you do it.

zip -s 5m file.zip myBigFile.mov

That cmd will create these files with file size capped at 5mb


To get your original file back, install 7zip.

brew install p7zip

Then run the following to extract your original file(s) back

7za x file.zip

There are other ways but I found the above the easiest.

Ref: https://superuser.com/questions/336219/how-do-i-split-a-zip-file-into-multiple-segments

Show download history in osx

Open a terminal and run the following command.

sqlite3 ~/Library/Preferences/com.apple.LaunchServices.QuarantineEventsV* 'select LSQuarantineDataURLString from LSQuarantineEvent'

If that’s alarming, you can add the following line to your .bash_profile file to clean up the history from time to time.

sqlite3 ~/Library/Preferences/com.apple.LaunchServices.QuarantineEventsV* 'delete from LSQuarantineEvent'

Ref: https://osxdaily.com/2012/07/12/list-download-history-mac-os-x/

Flexbox Defense

This is a fun way to learn css flexbox in a tower-defense game.


Shortcut to insert new rows in Google Spreadsheets

First select a whole row, then do Opt Cmd =. That’s option key, command key, and the equal sign key.

I am using Chrome on osx.

There are more shortcuts from this post: https://webapps.stackexchange.com/questions/44607/shortcut-to-insert-new-row-in-google-spreadsheets


Photoshop in a web browser, pretty amazing!


brew update is stuck

There is no output, no errors, no nothing. It just sits there.

Maybe related to this, who knows? https://github.com/Homebrew/brew/issues/3285

So I reinstalled brew.

/bin/bash -c "$(curl -fsSL https://raw.githubusercontent.com/Homebrew/install/master/install.sh)"

But then the install process is stuck at this line

==> /usr/bin/sudo /usr/bin/xcode-select --switch /Library/Developer/CommandLineTools

After some googling, apparently it’s caused by some combination of osx and xcode, see here: https://github.com/nodejs/node-gyp/issues/569. So I ran the following to fix the issue. 

sudo xcode-select -s /Applications/Xcode.app/Contents/Developer

But then after Ctrl-C and reinstall brew, I got stuck at another line, seems like it did a git reset HEAD but stuck right after.

I tried a few other things but nothing could pass that point. Then just random guessing I checked my Software Update, and saw a 5Gb osx update sitting there waiting, I was like, why not?

So update osx, reboot, then magically brew starts working. =)

Get real page source

Nowadays with all these javascript frameworks if you just do a view page source, you will only get the skeleton app div with a bunch of script tags. To see the expanded real page source, type in the following in the web console.


That will copy the computed dom to your clipboard, then you just need to paste it to your text editor. You will see all the other dom nodes which the js files added to the app div.

Ref: https://stackoverflow.com/questions/6364138/how-to-get-fully-computed-html-instead-of-source-html

Watch these videos before looking for a new car

Kevin Hunter, who worked at car dealerships before, gives the inside scoop of what’s happening at the car dealerships. I have experienced a few things he talked about in the past. These videos are definitely worth watching before heading to the car dealerships.

Personal information price tag

Here is a nice blog post on how much things related to personal information (e.g. credit cards, driver license, etc) are sold on the dark web.


Financial Statements

Here is a nice tutorial on financial statements.