Hear me taste the running man

Better array search

Tuesday July 21, 2009 | Comments (View) |

Update: Added more data to show differences.

During the journey of finding a better linear array search function in javascript, I decided to write my own. I decided to take a different approach. Here’s the outcome.

Array.prototype.small_search = function(search) {
    if (this[0] === search){ return 0; }
    var s = '\x00';
    var a = this.join(s);
    var b = a.search(search)-1;
    return a.substring(0, b).split(s).length;
};

With an array of less than 150 elements, it is much faster than Dustin Diaz’s in_array function. While they aren’t the same, his can be adapted to return the index also.

The only downside with my function is that it becomes much slower after the array length is larger than 150 elements. So, if you have a small array, go ahead and use this, otherwise use Dustin’s.

Times

Array Length: 5
small_search: 0.020ms
in_array:     0.098ms

Array Length: 10 small_search: 0.024ms in_array: 0.084ms
Array Length: 50 small_search: 0.042ms in_array: 0.095ms
Array Length: 100 small_search: 0.069ms in_array: 0.106ms
Array Length: 150 small_search: 0.087ms in_array: 0.111ms
Array Length: 300 small_search: 0.203ms in_array: 0.137ms
Array Length: 500 small_search: 0.418ms in_array: 0.132ms
Array Length: 1000 small_search: 0.813ms in_array: 0.138ms
Array Length: 5000 small_search: 3.530ms in_array: 0.312ms
Array Length: 10000 small_search: 6.718ms in_array: 0.441ms

Test it out on your own and come back with results.

How To: Splitting large text files into smaller ones

Friday May 29, 2009 | Comments (View) | bash unix

Let’s say you have a huge text file with couple million lines. Now you want to split it up into 100, 200, or 300 line files. Bash makes it pretty easy with split.

In Bash:

split -l 500 file.txt

That splits up the file file.txt into 500 line chunks. What is produced are files such as xaa, xab, xac and so on.

Be sure to do man split for more options.

How To: Find the size of a directory

Thursday May 28, 2009 | Comments (View) | bash unix du awk alias update

Sometimes it’s very useful to know how much content is in a directory without opening a GUI interface.

In Bash:

du -cks * | sort -n | awk '\''BEGIN { split("KB,MB,GB,TB", Units, ","); } { u = 1;while ($1 >= 1024){$1 = $1 / 1024;u += 1;}$1 = sprintf("%.1f %s", $1, Units[u]);print $0;}'\'' | tail -11

I would suggest adding this to your bash aliases as ducks.

Output looks something like so:

~ > ducks

4.0 KB p
72.0 KB Music
24.1 MB Sites
35.0 MB Downloads
433.3 MB Dropbox
937.5 MB Movies
3.5 GB Library
6.3 GB Desktop
11.7 GB Documents
16.5 GB Pictures
39.5 GB total

~ > _

Update: My good friend Clayton suggested a much simpler way. The only problem is that the output is not sorted.

du -h -d 1

The output is the whole directory. I truncated the output to show the last 11.

~ > du -h -d 1 | tail -11

6.3G	./Desktop
 12G	./Documents
212M	./Downloads
433M	./Dropbox
3.6G	./Library
8.0K	./Movies
 72K	./Music
 17G	./Pictures
  0B	./Public
 24M	./Sites
 40G	.

~ > 

Update #2: Some systems do not accept the -d flag. This can be replaced with the --max-depth flag, like so:

du -h --max-depth 1

How To: Remove Duplicate Lines From A File

Thursday May 28, 2009 | Comments (View) | bash unix awk

Sure you can load up a bulky editor and use its tools to do that, but why not do it in much faster in bash with awk.

In Bash:

awk '!x[$0]++' in.txt > out.txt

Wasn’t that easy?

Command, Option, & Shift Symbols in Unicode

Unicode does define some other characters which are sort of Mac-specific.

⌘ - ⌘ - ⌘ - the Command Key symbol
⌥ - ⌥ - ⌥ - the Option Key symbol
⇧ - ⇧ - ⇧ - the Shift Key symbol
⎋ - ⎋ - ⎋ - the Power Button

Note: The Power Button and Shift Key are not Mac-specific. The power button is described as “broken circle with northwest arrow”, or an escape character from ISO 9995-7. The shift key is described as an “outline up-arrow”.

Even though these are defined in standard Unicode, there is no guarantee that they will exist in the font of the receiving browser, but they’re at least globally defined, so they’re fair game.

Keyboard Shortcut to Help Search Box

Wednesday May 27, 2009 | Comments (View) | mac shortcut

If you haven’t figured out how Mac OS X 10.5 (Leopard) help search box allows you to search menu items, check out Chris Pirillo demoing the feature.

The problem for me is that I’m a keyboard person. Over 90% of my day, I barely touch the mouse. Now, to get to the help search bar with your keyboard, just press:

⌘ (Command) + ⇧ (Shift) + ? (Question Mark)

Find & Replace in Linux/Mac

Wednesday May 27, 2009 | Comments (View) | bash unix mac

This is a quick one liner to find and replace strings in *nix. You can use this in your Mac terminal or Unix prompt.

In Bash:

find ./ -type f -exec sed -i 's/FIND/REPLACE/g' {} \;

Example:

find ./ -type f -exec sed -i 's/signin/login/g' {} \;

Firefox & Input Field Width

Tuesday May 26, 2009 | Comments (View) | css firefox mozilla CSS box model HTML

Hate the 2px difference you get when you apply a width on your input fields in Firefox?

Try this in CSS:

input, textarea, select{-moz-box-sizing: border-box;}

See how many Kernel Panics your Mac has had

Tuesday May 26, 2009 | Comments (View) | bash mac

In bash:

ls -1 /Library/Logs/PanicReporter/ | wc -l

I’ve had 5.

Scroll to bottom of page.

Friday May 22, 2009 | Comments (View) | javascript

In javascript:

window.scroll(0, window.document.height);