Category: bash

Some Simple Regexes for Finding If Statements

I know almost nothing about regexes, these are just some useful ones I created for checking code style, if statements specifically.

Find single line if statements (Useful when your coding style requires adding curly braces to everything):

/^ *if \(.+\).*(;)/igm

regex101

Find multiple line if statements (Useful when your coding style favours less lines):

/^ *if \(.+\).*({)/igm

regex101

Regex101 is really impressive.  You can paste a regex and check it against some test inputs.  The best part is the description of what each symbol in your regex does and even what some of the combined parts do, such as various brackets around groups of expressions.

How To Automatically Download All of Your YouTube Favourites

FireFox add-ons such as 1-Click YouTube Video Download are good but one must visit every video and manually save it. I have a lot of favourites and I wanted to back them up with as little effort as possible. Here is how.

You will need youtube-dl. It is available via yum/apt-get however the version provided may be quite old (In Fedora 14 it did not support –playlist-start and –playlist-end).

Create a new playlist and add all the videos from your favourites (Note: A playlist can only contain 200 videos if you have more than than this you will have to make multiple playlists and repeat this process for each one).

Click on “Play All”. Copy the URL from the address bar for the first video when it tries to play (You only need this bit: “http://www.youtube.com/view_play_list?p=AE198A14013A3005”).

Now tell youtube-dl to download the videos in the playlist:

python ./youtube-dl.py --title --ignore-errors --playlist-start=1 --playlist-end=200 http://www.youtube.com/view_play_list?p=AE198A14013A3005

If you had more than 200 videos repeat this process for the ones that didn’t fit in the playlist.
This should work for other people’s playlists too.
You might want to make a note of the latest video in your favourites so that the next time you can backup only the new videos.
This process still requires some user interaction, if you find an even easier way where I can just say, “This is my user name, make it happen”, I’d love to know about it.

Git: Review the Changes in a file and Optionally Revert A Particular Change

# Review all the changes in a file, giving us a chance to revert a particular change
git checkout -p path/to/file/to/partially/revert

Note to self: Move this to a useful Git tips post.