Writing Grex/Sed in Python, Perl, Emacs Lisp
also updated. Python: Find/Replace by Regex Text Pattern
for a Perl version: Perl: Find/Replace on Multiple Files
emacs lisp version: How to Write grep in Emacs Lisp
for keyboard freaks. updated. Exotic Ergonomic Keyboards
some intermediate git tips, on its own page: git Frequently Asked Questions
How to set git output non-interactive?
there's no way. Just send it to a file then view that file.
git log > 888888
If you are using emacs, you can place cursor on the file path then call ffap (see: Emacs: Open File Path Under Cursor Fast), or install “magit” package for git. It's in MELPA repository. See
A Guide on Emacs 24 Package System.
How to make git display date in ISO format?
Use --date=iso.
git log --date=iso
See also: git Tutorial
Note: for those of you who know me, i got the keyboards free, but my opinion isn't bought, judge for yourself.
video. how i write blogs in emacs
lots pictures now. Computer Keyboards, Layouts, Hotkeys, Macros, RSI ⌨
Been using the Truly Ergonomic keyboard for 5 months now. Added my experience here at bottom: Truly Ergonomic Computer Keyboard Review.
updated. Python ＆ Perl: Traverse Directory
uploaded several of my file utils in perl to github. https://github.com/xahlee/xahscripts/tree/master/file_util
Perl: General Function for Sorting Matrix
wrote that in 1999, and used it in production back then. In 2006, i wrote a Python version but was incorrect. Going to write a Python version again.
Ruby, JavaScript, versions welcome.
there's a fantastic heart-shaped keyboard. If you haven't seen it already, see at Keyboard Porn to Infinity ⌨ ∞. The guy plans to manufacture it. To keep updated for news, watch his website at http://launch.keyboard.io/
the quality of a programing language, can be judged by how much of it can be explained by its syntax alone.
with this criterion, the order are roughly: Mathematica ≻ PHP ≻ Lisp ≻ JavaScript ≻ Ruby? ≻ Perl ≻ Python ≻ Java.
this is also the most important criterion in judging a language.
If you have coded one of {Haskell, ML/OCaml/F#, erlang, Scala, Pascal/Ada, Lua, tcl, APL, SmallTalk, PostScript}, i'd be interested in your opinion on their placement in the above. (you should have coded in the lang for a few years)
A new function key manufacture. See: http://www.access-is.com/custom_keyboards.php
that's nice if you are the master of function keys. See also:
thx to David Rogoff
inspired from emacs lisp doc. Logic Write Style: the Incongruousness of the Word “Actually”
to convert HTML to PDF on Linux, you can use wkhtmltopdf. It's based on webkit, the web browser engine used by Safari an Google Chrome.
# install sudo apt-get install wkhtmltopdf
wkhtmltopdf my_resume.html my_resume.pdf
if you just have one single file, you can also use libreoffice.
# install libreoffice sudo apt-get install libreoffice
Type libreoffice to start it, then, open the HTML file, then use menu 〖File ▸ Export…〗.
updated. Perl ＆ Python: Regex Example
on its own page. Tech Writing and Unix Humor
found a chinese site with tons of photos on KBC Poker keyboard. See links at: KBC Poker Keyboard, Ducky Keyboard (thx to cloudsben)
the Happy Hacking Keyboard, model “professional 2”, don't even have arrow keys. The Idiocy of Happy Hacking Keyboard
updated. Unicode Full-Width Characters
also updated. Python: Find/Replace by Regex Text Pattern
for a Perl version: Perl: Find/Replace on Multiple Files
emacs lisp version: How to Write grep in Emacs Lisp
also updated. Python: Find/Replace by Regex Text Pattern
want color diff?
sudo apt-get install colordiff
updated. discovered big chunck of code in emacs lisp using math symbols as function/variable names. Programing Style: Variable Naming: English Words Considered Harmful
why you need to swap middle/right mouse buttons, and how. Swap Mouse Buttons: Right-Click ＆ Middle-Click
Vote which one you want me to work on. Tell your friends please. http://pledgie.com/campaigns/19973
updated. Probably final form for a while. Linux Firewall Tutorial: iptables ＆ netfilter
more update. Some important problems of XML syntax. Refresh page. Nested Syntax Design: XML vs LISP
every now and then, people will ask what's the best keyboard for emacs. I thought i'll start a article dedicated to that. Best Keyboard for Emacs
updated. New photo. Kinesis Contoured Keyboard Review and RSI
excursion. 2 hands pen-spinning, by yours truely.
JavaScript in 3 hours. More massive update. Array manipulation, and others. JavaScript Basics by Example
discovered a keyboard tool, KeyTweak. See: Microsoft Windows: Keyboard Layout and Key Macro Tools
spent the whole day improving this JavaScript app for Unicode. Unicode: Arrow Symbols ← → ↑ ↓.
article hit hackernews. https://news.ycombinator.com/item?id=5184907 ◇ Why Python's Lambda is Broken and Can't be Fixed
updated. Keyboard Hardware Design Flaws
one of my article hit HackerNews. https://news.ycombinator.com/item?id=5517593
What Does it Means When a Programing Language Claims “Whitespace is Insignificant”?
updated. Unicode ASCII Art Collection
for unicode freaks. Allograph
updated. Unicode ASCII Art: Font Emulation
I have always wondered about this. You know that retrieving a indexed item of array takes O(1) time. Why is that? You have n things, and you want the kth item. It should be O(k) for kth item. It is impossible to get it with O(1).
The answer can't explained in software or algorithm. It really have to do with how the hardware is implemented. This article explains: 〔Why is Indexing Faster Than Binary Search By Yin Wang. @ yinwang0.wordpress.com…〕
updated, on its own page. Linux: Job Control Tutorial
cum, money. 19dfoa3Q7oehm9MwCULQzBG8vqfCaeMazH cum all you want on me. i swallow. #bitcoin
“when a man swallows, his destitution can be seen.” —Xah Lee
major revamp. Xah's CSS Tutorial
on its own page. IBM Model M keyboard, Unicomp
wow, Richard Stallman got into a quarrel with Linus on stage in FOSS'13 London and a riot started.
am very happy, that i've settled on this Unicode symbol ⁖ to represent “e.g.” or “example”. The name of that symbol in Unicode is THREE DOT PUNCTUATION. See bottom: Symbol, Semantics, Design: Unicode for “e.g.” (exempli gratia)
A nice essay: 〈Programming Languages Have Social Mores Not Idioms〉. Added the link to the bottom of Programing: Why Idiomatic Programing Are Bad.
on its own page. Python Libraries for Scientist
slight facelift. Xah's Java Tutorial
3 articles on the statet of the onion. Perl is not dead, but is dead end.
〔Texinfo 5.0 in Perl By Dave Cross. @ perlhacks.com…〕
〔Perl is not Dead, it is a Dead End By Stevan Little. @ speakerdeck.com…〕
〔Goodnight, Parrot By Chromatic. @ www.modernperlbooks.com…〕
Microsoft Sculpt Comfort Keyboard. Space bar is now split into a ⌫ Backspace key.
more words added to the idiotic aspell. Go github at bottom to grab it. aspell's Dismal Vocabulary Size
hot from the oven. learn ngnix in 1 hour!
added a photo of Commodore 64 keyboard. Keyboard: Control vs Capslock Position
MERCURY ☿ VENUS ♀ EARTH ♁ ⊕ MARS ♂ JUPITER ♃ SATURN ♄ URANUS ♅ ⛢ NEPTUNE ♆ PLUTO ♇. Added some interesting notes about these symbols, see bottom. Unicode Ancient Astronomy Symbols ☿ ♆ 🌛 ♋ (you might need to refresh the page)
new collection. documentation idiocy collection
facelifted. Python Documentation Problems
updated. How to Improve Python Doc; Notes on Rewriting Python Regex Doc
After 8 years, Python doc haven't improved much. There are complaints about Python doc about every year in Python mailing list, and Python doc wiki constantly crop up, but the python priests always flame and turn it down.
learned a new linux command. man lsmod. It shows the status of modules in the Linux Kernel. Basically pretty print 〔/proc/modules〕
sitewide replace all the Google Map and Google Earth icons.
the AIRPLANE was used for Google Map before because i couldn't find a better Unicode symbol. Same for Google Earth. The CIRCLED PLUS was a old astronomical symbol for Guia, mother earth. Unicode 6 now has better symbols, but i still can't find one that more properly represent map. Can you?
if you need fonts for Unicode 6, see Unicode 6 Emoticons and Supporting Fonts
here's a examples of pages that contain Google map/earth links:
eureka, i just found the name of my lang. laputa!
PS Gulliver's Travels. PART III. A VOYAGE TO LAPUTA, BALNIBARBI, LUGGNAGG, GLUBBDUBDRIB, AND JAPAN.
Xah Edict of the Day: anyone using the term REPL is to be despised upon immediately.
How should one call REPL then?
command-line user interface (CLUI)
Why should one call it CLUI?
Because, first of all, you are a idiot. That's what that I is for. And U don't have a clue. That's the CLU is for.
It's called CLUI because that's what it is.
REPL is like calling a car “gas combust crank run”. It's fashionable because you are a Tech Geeker and delights in jargon to hint your in-group status.
read more at REPL Jargon
on its own page. USB3 Drive Speed
updated on how to fix. Fix Defective Keys in Comfort Curve Keyboard
much more info about the OMeta lang at bottom: Proliferation of Computing Languages
started to work on Linux iptables tutorial. Linux: iptables Basics
another keyboard layout. qwpr Keyboard Layout. Also, the Workman layout has a much improved home page, with a active forum. See bottom: Computer Keyboard Layouts: Dvorak vs Colemak vs Workman
lol. perl added a say in v5.10 . It's like print but adds newline at the end. But you have to use v5.10; first. Quote from perldoc -f say.
say FILEHANDLE LIST
say FILEHANDLE
say LIST
say Just like "print", but implicitly appends a newline. "say LIST"
is simply an abbreviation for "{ local $\ = "\n"; print LIST }".
To use FILEHANDLE without a LIST to print the contents of $_ to
it, you must use a real filehandle like "FH", not an indirect
one like $fh.
This keyword is available only when the "say" feature is
enabled; see feature. Alternately, include a "use v5.10" or
later to the current scope.
these days, perl monger remnants try to revive perl from death bed, and talk about “modern perl”. LOL. the very name is funny. Am guessing the next step would be post-modern perl? or is that already a trope?
learned a new Linux command: watch. ⁖ watch netstat.
this is useful when you want to run some command regularly and itself doesn't have auto-update.
thx to Ryuutei Sebastien BLANC
I don't know much about Operating System. I was just wondering whether or why the networking component is part of the kernel. Then, found this fantastic map. Linux Kernel Map.
learning notes. Linux: What's Netfilter, iptables, Their Differences?
Linux networking. iptables man page.
ACCEPT means to let the packet through. DROP means to drop the packet on the floor.
Note that we drop it to the floor, not, river or lake, as Microsoft might.
Xah's Edu Corner of the Day
there are 2 types of firewalls. Complicated and Uncomplicated. Linux supports the uncomplicated type, called ufw. It stands for Uncomplicated Fire Wall. Type man ufw in terminal to read its doc.
the complicated type is related to the math concept of complex number.
PS this post is of import due to its affinity to the field of linguistics, category theory, the theory of archetype, and ontology.
added a video review of the mech4 mechanical keyboard. Real high quality keyboard. Gaming Keyboards: Levetron, BlackWidow, Sidewinder. Also added them is the BlackWidow from Razer.
added domino tiles, mahjong tiles. Sports ＆ Games Icons ⚽ ⛷ 🏁 🂡 ♞
recently discovered proper symbol for the Alt key, and few others. Example:
charmap, there's a note that this symbol can be used to mean “control”. (haven't found out what's the source of the note. Might be from ISO standard. Anyone knows?)btw, when you plugin a Mac keyboard into PC, or PC keyboard into Mac, you'll notice that Mac's ⌥ Opt = PC's Alt, and likewise for ⌘ Cmd and ❖ Win. I always wondered if the keys send the same signal or perhaps it's the OS that's doing the remapping. Answer: The keys send the same signal. So, this means the keys are just difference in key label, and the physical positions are swapped.
you can see all these here Unicode: Keyboard Symbols, UI Icons ↹ ⌫ ⌘ ✉ ✍ ⌖
heard a new language OMeta. Home page at http://tinlizzie.org/ometa/
from a comment at Pattern Matching vs Lexical Grammar Specification
now complete. Unicode Music Symbols 𝄞 ♩ ♪ ♫ ♬ 🎸 🎹 🎻 🎷
playing cards in Unicode. Sports ＆ Games Icons ⚽ ⛷ 🏁 🂡 ♞
learned a new linux command tree. It prints a dir in a visual tree format, similar to pstree. You have to install: sudo apt-get install tree. See also Linux: Most Frequently Used Shell Commands.
learned today that Apple's color font, is actually color font technology, not secondary step of replacing fonts by images. See screenshots here: Unicode Icons: Food, Drink
Unicode is such a beast. Y'know, it encompasses all written languages, including ancient dead ones. But that's not all. When you dig into Unicode symbols, you see the thousands of math symbols, printer's symbols, forgotten punctuations, ancient astronomy symbols…, some of which we use today but don't have any clue of their origin. ⁖ ☤ ☧ 卐 ☥ ☯ ⚸ ….
See, for example: Unicode: Dingbats, Cultural Symbols
you might be curious, and started to read about what they are for. I started that way some 5 years ago. First due to my love with math symbols. After few years doing it casually, you realize, to really understand all the symbols, their origin, history, can take you few years to decades. Not even counting the alphabets of dead writing systems.
unicode 6 added over 2k chars. 600 of them are emoticons, and many others are pictographs. Unicode 6 came out in 2010, but there's still not that many fonts supporting all those pictogram. On Mac, it's most beautifully done. See screenshots at bottom of Unicode Icons: Food, Drink. On Window, Microsoft came up with Segoe UI Symbol-12, in 2012, as part of Window update. On linux, nada, but you can download the free font Symbola, which is very high quality. See bottom here: Unicode 6 Emoticons and Supporting Fonts.
to install font on Ubuntu, just unzip it, and double click it should do.
all i ever needed to know about keyboard, i didn't learn in kindergarten. Three hundred fourty images of keyboards. Keyboard Image Index
wrote a JavaScript app. Goto Unicode Emoticons, Faces 😸, hover your mouse over (or click if you are on tablet). Unicode name and char number will show.
also created the following pages.
python tip. To get image dimension (width and height in pixels), you can do:
# -*- coding: utf-8 -*- # Python import Image print Image.open("/home/xah/pictures/cat.jpg").size
but for python 3, the image library isn't there yet.
about a month ago, i decided to replace all use of “e.g.” on my site to the Unicode “ℯℊ”. Symbol, Semantics, Design: Unicode for “e.g.” (exempli gratia)
But now, it's like The Tell-Tale Heart, i confess, i can no longer tolerate my incorrect use of symbols. The scripted e ℯ is usually used for Euler's number in math. The scripted g ℊ has no popular designated meaning. They in no way means “exempli gratia”. So, now i decided to replace them all to the more symbolic ⥱.
My writing's already filled with willful eyesore to the establishment. (☛ The Writing Style of Xah Lee) What's with just one more symbolic idiosyncrazy?
but i take console that i'm in the same class as Stanislaw Szukalski, Robert Crumb, Jonathan Swift, Friedrich Nietzsche, Leo Tolstoy. No doubt.
Kinesis has a new generation of their split keyboard, Freestyle 2. See: 2-Piece Split Keyboards
Ruby's predefined global variables is not documented, but Ruby 2.0, which came out few days ago, fixed that. Ruby: List of Predefined Global Variables
hot keyboard news! Logitech now also makes mechanical keyboard. Very Cool! amazon Full review. Logitech Gaming Keyboards
There are 3 major form factor in keyboards: • ergonomic. • split. • normal (straight). If you don't care for ergonomic or split ones, then, i think this is the best among straight, for programers, because:
You can compare this with lots other mechanical keyboard in straight form. First, they all start about at least $70, and lots of them are over $100, many at $120 without much features. Many of them don't have any multimedia keys, nor sound wheel. Some don't have function keys.
the other one that i think is as good is Corsair K60, K90
see also: Best Keyboard for Emacs
updated with photos. HP-28S Advanced Scientific Calculator
discovered a linux phenomenon.
y'know, linux has package managers, ℯℊ apt-get, yum, pacman.
now, that's heaven. Search, install, done. No compilation and potentially hours reading README INSTALL fsck and gcc make version compatibilities. Universal, systematic.
but, NO.
you realize, when you get slightly deeper into python, ruby, etc, they don't recommend using the system's package manager. They recommend compiling yourself, or, use their own system.
Why? because the system ones are often outdated by a year or so. And when you get deep in dev, you need to manage several different setups, lib versions. So, python has pyPM, york, and others, perl has whachamafsck and others, ruby has rvm and others. (and ruby rvm is shell script muck on drugs)
you see, from my recent experience, it's not just one simple one per lang. It's several competing ones. You have to research and wikipedia and stackoverflow and feel the pain then settle which to use.
it's rather complex. Not trivial. How to Install Ruby; What's RVM, Gem, Rake, Bundler, RDoc, ri, irb?
as another example, let's say emacs. Now, that's where i can claim knowing a thing or two. When you apt-cache search emacs, you see tens of stuff flying by, many of them elisp packages (ℯℊ major modes). emacs modes from apt-get? LOL. Get outta here! You want use the one from emacs 24 instead, list-packages, and repositories of MELPA (and or OTHER repositories!).
(☛ A Guide on Emacs 24 Package System)
AND, no, there's not just one emacs packages system, there are competing ones, even competing repositories. So, if you didn't spend years wallowing in emacs community, you wouldn't know.
how i learned to stop worrying and love the bomb…
discovered that the Ducky keyboard from Taiwan makes real quality keyboards. Check out their website. I don't think you can easily buy it in USA though. But you might be able to buy from the company's site via shipping. (KBC is also quality.)
in your code, do you prefer camelCase or under_score?
then, Christian Herenz alerted me, that this paper calls it “pot_hole_casing”. LOL!
〔Best Practices for Scientific Computing By D A Aruliah, …. @ arxiv.org…〕
thinking about it, that term makes much more sense than under_score. You see, camelCase is named visually. So, “pot_hole_casing” is a nice complement. Without visual clue, the phrase “camel case” can still convey, but “underscore” wouldn't, but “pot_hole_casing” would. Thus, it's a superior term.
see also: Programing Style: Variable Naming: English Words Considered Harmful
Kurt Schwehr is a python expert and ocean geologist.
I'm trying to get deeper into python, and asked him what's some Python packages. Here's his answer. (source)
Hi Xah, That's a great question that is likely going to get very different answers from different people. First, my list that is less specific to my fields of work... general: ipython, cython, argparse, virtualenv, distribute. I have never gotten into cython myself, but the resulting APIs that use it are definitely very good.
Now the list that includes stuff related to my work topics: matplotlib, scipy/numpy, lxml, pandas, shapely, and gdal (not my favorite python API design, but the functionality is critical).
And finally a list of packages are amazing (and amazingly daunting)… django, twisted
Here's what these packages are. Items are roughly arranged by category, general interest first.
check out Kurt's site at http://schwehr.org/.
small python list tip. negative stepper starts from right
when the stepper is negative, it starts from right. ℯℊ ‹list›[::-1] reverses the list. (when the first index is empty, it default to 0, and when second index is empty, it defaults to the index of last item.)
# -*- coding: utf-8 -*- # python 3 print(["a", "b", "c"][::-1]) # ['c', 'b', 'a']
thx to https://twitter.com/Ryuutei
Programing Challenge: Replace String Pairs
should be fun. This problem started in elisp for me few years ago. Over the years, tried several elisp approaches… but overall i was stung twice. Few weeks ago, found a bug in my code. Rewrote it with a new algorithm thinking it's much better, but bang, another bug. That is, incorrect behavior.
Now i think i have a good solution, but still has certain limitations. So, am posting this as a fun coding problem, pulling on the talent pool.
am posting this as a general programing problem, not specific to emacs lisp. I do have a elisp solution, but can be easily translated to any other lang.
Programing Language Design: Why Lisp Macro Sucks (YMMV very much!)
oldie but goodie. In light of the recent John McAfee incident. ZIP, Open Source, Mother-Son Relationship
I don't think this is suitable for programers, but a fun funky keyboard, with mechanical keys (Cherry MX Black). Levetron Mech gaming keyboard (updated, new page)
drew the layout diagram of Happy Hacking Keyboard in SVG. Happy Hacking Keyboard
PS if you gonna buy it, buy it from my amazon link!
the new lang julia is quite interesting. A order faster than most other langs. So so many langs, which you gonna choose? Proliferation of Computing Languages
found a better way to make mouse wheel accelerate in Firefox. Updated: Firefox: Set Mouse Wheel Scroll Speed, Backspace for Previous Page, Autoscroll
update. added a 3 video reviews. Logitech Trackball Mouse Reviews
trackballs are especially nice when you turn on auto-raise. That is, you hover pointer to a window and it automatically comes to the front. You can turn this on in Microsoft Windows or Linux (but not Mac). (☛ Single-click Open File, Auto-Raise Window, for {Windows, Linux})
auto-raise is nice because it saves you lots of clicking. Once you get used to it, it's so smooth, no clicks or keystrokes.
trackball makes this even better, because when you have auto-raise on, you don't want to move the pointer unnecessarily. Trackball by nature doesn't move pointer, while with mouse, one tends to move it about.
in Ubuntu Unity, they started to have a fancy feature called “auto-click”. That is, whenever the pointer rests on a spot, it automatically do a click. So, with this, you don't even need to click on tabs, or boxes, anymore. I tried it for 5 minutes, but haven't decided i want it, because it's too easy to unintentionally click on something. You have to always find a inactive spot to rest your mouse. (does anyone know how to turn this on in xfce?)
lisp logo latte art. see Xah Emacs Blog
Emacs, LISP, Ruby, and computing history. Ruby Creator Matz on How Emacs Changed My Life
started to read a blog titled 〈Write Yourself a Haskell... in Lisp〉.
wow, that's interesting. The net really got advanced geeks. I myself have written a perl package that emulated Mathematica functions ten years ago, but it was not something to send home about, because it doesn't do parsing. It just implement some functions of Mathematica in perl, all perl syntax. (☛ Perl Module: Tree::Matica (Mathematica Tree Functions in Perl))
then, the second paragraph, it says:
«We're not going to bother with parsing: our input programs will be S-expressions.»
lol.
if you don't do parsing, you are skipping the hard part. And the title 〈Write Yourself a Haskell... in Lisp〉 becomes deceptive, or, marketing.
wrote this. validate my website Google Analytics code. 〔https://github.com/xahlee/xahscripts/blob/master/validate_website/check_google_analytics.py3〕 Too bad that github doesn't recognize the “.py3” suffix. It makes things a lot easier.
new. Python 3: Operators
for some reason, Unicode in Mac are in color. Updated with screenshots. Unicode Icons: Food, Drink
pedobear is coming to town ᶘ ᵒᴥᵒᶅ Unicode Smilies (◔ ◡ ◔)
hot from the press. Learn Python 3 in one hour. Python 3 Basics
updated. aspell's Dismal Vocabulary Size
How to auto sync X11 primary selection and its clipboard?
answer added at Linux: Commands Related to GUI Apps
What's the linux command line to put things in trash?
You can do gvfs-trash filepath.
The FreeDesktop.org Trash specification By Mikhail Ramendik. @ www.ramendik.ru…
updated: Linux: Commands Related to GUI Apps
new page, with Microsoft mouse. Ergonomic Mouses: Evoluent VerticalMouse, Microsoft Natural 6000
note, jwz uses the Evoluent VerticalMouse. See Celebrity Programers with RSI (Repetitive Strain Injury)
Python3's 2to3 converted my use of lambda to list incomprehension.
- return len(filter(lambda x: x == os.sep, os.path.abspath(d))) + return len([x for x in os.path.abspath(d) if x == os.sep])
hey, is there no respect to my style?
git force pull.
git fetch --all # get latest from remote but without merging into local git reset --hard origin/master # rid of all local state
looks like Andrew Auernheimer (aka weev) is going to jail.
He's a grey hat hacker. You can read about him at Wikipedia here Weev
he published a essay on Tech Crunch here: 〔iPad Hack Statement Of Responsibility By Andrew Auernheimer. @ techcrunch.com…〕
new found. Fantastic. Linux: Best Image Viewer for Random Slideshow of Subdirectories
i wanted to know the general mechanism in Linux to associate file extension with executables (for when user clicks a icon in GUI), and i wanted to know how to do this asso by command line.
it seems there's no standard way. Here's 2 best links from helps i got.
Arch Linux documentation consistently came up the best when i had some Linux questions. I started to read about Arch Linux a bit. I like their philosophy. I think it'll be my next linux to try.
while Ubuntu community is like …
Pattern Matching vs Lexical Grammar Specification
redraw the parser diagram in Inkscape. ♥ Inkscape.
git diff a file in staging area vs a previous commit.
git diff --color --cached a6efe85 xahlee_info/comp/blog.html
don't forget the 「--color」 part.
to make git always color in diff, do:
git config --global color.ui true
To find out what a key or key-combo does, type :help then press the key, then Enter ↵.
the blog i wrote few days ago about TCP/IP is now on its own page. quick random jot-downs, on TCP/IP, on Tech Writing
meanwhile, i discovered a much better book. 〔《Sams Teach Yourself TCP/IP in 24 Hours (5th Edition)》 amazon〕
the 〔《TCP/IP Illustrated, Volume 1》, 2nd edition (2011). amazon〕 is classic, but Academic, verbose, hard to undersand, and the latest edition isn't well written. The Sams book is much more practical.
updated. Unicode in Python 🐍
article withdraw. Couldn't verify what i said now.
if you have lots bookmarks, and if you want to edit them in a text editor, here's how.
Here's why you might need to do this. I have 7 local links as bookmark. Today i moved the dir. So, i need to update all links in the bookmark. If you use the Firefox GUI to edit (【Ctrl+⇧ Shift+o】 or menu 〖Bookmarks ▸ show All Bookmarks〗), it's gonna be one by one, tedious. I rather use a find/replace operation.
The Firefox bookmark is at 〔~/.mozilla/firefox/wix458pt.default/bookmarkbackups/〕
It's a JSON file. Open that, edit it, save.
Now, goto Firefox, open the bookmark manager 【Ctrl+⇧ Shift+o】, then menu 〖Import and Backup ▸ Restore ▸ Choose File…〗, then select the file you just edited. To show hidden file, press 【Ctrl+h】.
That's it.
Is my Linux kernel 32 bits or 64 bits?
Type getconf -a | grep LONG_BIT
Linux: How to Find {kernel version, Distro, CPU, RAM, Disk Size} Info
in Linux, if you are using xfce, then the folder viewer (aka file manager) is Thunar. It doesn't have a option in preference to show hidden files (those starting with a dot). But you can show by 【Ctrl+h】
on its own page. Why Python's Lambda is Broken and Can't be Fixed
new. A much better top. Linux: Monitor Processes, “htop” Tutorial
some quick random jot-downs, on computer networking, on tech writing.
in past 3 days, working day'n'night to review my tcp/ip know-how. haven't really touched that for like 10 years.
in the process, as usual, writing down notes that's tutorial-to-be.
it's quite time consuming to write. Most of it is draft, and lots just partial quotes from Wikipedia. (but, for this or any kinda endeavor, it's almost better to start somewhere rather than master-plan)
(and, you see, in my tutorials, i aim to write it in a particular style, which makes it more time-consuming, because on one hand i'm still learning, trying to avoid error, while, writing tutorial with a particular approach really calls for full understanding first.
Pertaining to style, there's the approach aspect and writing (diction, grammar, syntax, format, etc) aspect. The writing aspect i've described here The Writing Style of Xah Lee, but i don't think i ever expounded my approach aspect.
But to illustrate quickly, for example, in language tutorial i treat the lang as piece of math written on paper, focusing on what you can see (i.e. what you typed) and observable behavior, and avoid the typical unnecessary mentioning of the garbage underneath such as int, float, IEEE number, memory, reference, pointer, “garbage collector”, compiler mumbo-jumbo, lang internal “model” (where each lang's priest sell you shit and believers buy it like hot cake), and spurious jargons particular to each lang community. (typical tutorials suck. ℯℊ in OOP, they like to mention fruit, banana, apple when trying to teach class hierarchy or inheritance. The worst example of incomprehensible techno-babble is Python's doc (and unix man). (☛ Python Documentation Problems) While the worst example of jargon-babble is the Perl doc. (☛ Perl Folks Try to Erase History!) The best example, similar to my style of approach, is PHP doc, Mathematica doc. (☛ The Idiocy of Computer Language Docs) ) )
(this quick post got ran on and now turns out to be masturbation. O, good for me. LOL)
btw, there's a O'Reilly book 《Linux Network Administrator's Guide》. Latest edition is 3rd edition, 2005. But all the online edition i found is 2nd (2000) or 1st, 13 years out of date garbage, and frequently cited online. Even the 3rd edition, is pretty much garbage. (and btw, the online edition, don't mention date or edition. You have to do some digging to find out what edition it is. Really hate that. (If you are a blog writer, please put a date on your articles, and your name in a well-lighted place. (yes you, hacker-types) Unless, you conspicuously, absolutely, wanted to be anonymous. In that case, put explicitly “by Anonymous”. (what most hacker-types do is, on one hand they don't want to be totally anonymous, they use a “handle” (aka nick), while, have all sorts of qualms and insecurities about their identity, while, they don't really want to be truely anonymous, they just want to make it a trip for those who want to identify the author, while, all this is really not thought out, it's just one of the behavior of the hacker-type mindset)))
Why the O'Reilly book is so bad? Of course, it's one of the first “open source book”, to please Richard Stallman's “Free Software needs Free Documentation” mantra. The problem is, the tech geekers don't really give a damn, they just want it $free$. So, there's really no incentive for O'Reilly to update it, or make their site of the book updated, other than the initial “we support geeks” marketing. So it's badly out of shape, while, commercial books on TCP/IP, you pay to get it on amazon, are much better quality. (☛ Software Freedom is Free Speech or Free Beer?)
btw, there's another free book, 〈Debian Reference, Chapter 5. Network setup〉, that's also pretty bad.
my current references, besides Wikipedia (and possibly following citation to standard publications such as RFC (aka Really Fucking Common)), is the 《TCP/IP Illustrated, Volume 1》, 2nd edition (2011). amazon Verbose to the bone, but at least trust-worthy info. (i much prefer Wikipedia actually) (i read few chaps of that TCP/IP book a decade ago.)
Updated. Best Trackball Mouse
learned that the ⌘ Cmd key and ❖ Win are really identical in keyboard hardware. They send out the same scancode. Similarly, ⌥ Opt and Alt are identical. Updated: Difference Between Apple and PC keyboards
breaking news from the emacs department. Even if you are not a emacs user, this might be interesting.
ErgoEmacs version 2.0 release candidate is out. http://code.google.com/p/ergoemacs/downloads/list
ErgoEmacs is a emacs with modernish interface, meaning, the keys for common commands such as open, close, save, copy, cut, paste, select all, are the same for any app on {Microsoft Windows, Mac OS X, Linux}
so, this means, you can use emacs right away, while, explore the power you constantly hear elite hackers talk about. Give it a shot.
much thanks to the Window programing guru David Capello (David wrote wrote many apps for Microsoft Windows, the most popular is probably the pixel editor aseprite http://www.aseprite.org/ check it out.)
in Python, when you have multiple print statement adjacent, the output may not be in that order. ℯℊ
print 1 print 2 print 3 print 4 print 5 print 6 print 7 print 8 print 9
i've been stung by this, wasted 20 min yesterday. I vaguely recall been stun by this in perl too. I think the issue is IO sync problem.
damn. can't reproduce it now.
used as cover image for my article index The Complexity ＆ Tedium of Software Engineering
spat with the redoubtable lisper, computer scientist Richard Fateman. Programing Language Systematic Syntax: Lisp vs Mathematica
my linux question. Ubuntu Linux: What's the Command Line Equivalent to Update Manager
been stung by this again. Idiotic Python.
# -*- coding: utf-8 -*- # python # a global array aa = [0,1,2] def f (): aa[0] = 88 # this is ok. global array will be updated def g (): aa = [] # WRONG! global array will NOT be updated f() print aa # prints [88, 1, 2] g() print aa # prints [88, 1, 2]
the tech excuse has to do with how Python looks up variables. i.e. Python's variable scope.
i really hate all these language with references or whatnot garbage underneath. Same complex thing happens when you copy list (thus you beget “deep copy”, “shallow copy”, “circular list”, sh�ts like that). Of course, the fanatics of each language will start to mumble about technicalities particular to each of their own, and accuse you no-unstand. YOU NO UNSTAND!
in general, functional programing language don't have these sh�t, especially Mathematica. Everything is just a copy. Old lispers, in particular the Common Lispers, also no unstand. Froth form over their mouths, and speakths of lisp's “object”, “internal representation”, “lisp reader”, et al.
see some past spats.
between Perl, Python, Ruby, my fav now is Ruby, absolutely, because:
updated. How to Use Unison for Syncing Files (Unison tutorial)
note that Unison is written in OCaml (☛ Xah's OCaml Tutorial).
Updated. Windows Programing: AutoHotkey Example Scripts
for much more on keys and tools, see latest at Xah Emacs Blog
updated: Windows: Best Anti-virus Software
on its own page. XML Syntax is Inferior Lisp Syntax?
new. Perl Basics. A bit rough, but i gotta start somewhere.
if you use a full keyboard with number pad, you should use it for function keys. Indispensible.
if you often work on laptop, then, i recommend F11 F12 for prev/next tab, and F10 for close. (【Ctrl+⇧ Shift+t】 un-close last closed, in Firefox, Google Chrome.)
rid of any key combos.
and, within emacs, you can easily set keys too. F11 F12 for prev/next user buffer, and F10 for close current buffer. (the commands are in ergoemacs-mode)
“recursion” — a central theme in this song. Björk — Bachelorette
here's recursion bonanza.
On the news, that there's a new zero-day exploit of Java. How to Disable {Java, JavaScript, Flash}, in {Google Chrome, Firefox, Internet Explorer 9}
What's a zero-day exploit?
software defects that are vunerable to hacking or virus attacks are sensitive to whether they are exposed to public for the first time. Because, once a virus or hack exploited that defect, companies or software experts will respond to it and more than likely to fix it. So, this means, the first time a virus or defect are exploited, it's the most damage done, that's Zero-day exploit.
coded this interview problem. Luhn Algorithm
old article, still relevant: Why Must Software be Rewritten for Multi-Core Processors?
Aaron Swartz (of Reddit fame) killed himself yesterday.
On my Microsoft Windows 7 machine, only Firefox display them well (missing just 2 characters).
All other browsers, Google Chrome, Safari, Opera, Internet Explorer 9, got nothing.
I do have Unicode 6 fonts installed (Symbola, Segoe UI Symbol). Somehow these browsers are not picking it up. (☛ Best Unicode Fonts for Programing) (☛ Unicode 6 Emoticons and Supporting Fonts)
On Linux, default setup of Ubuntu 12.04, none of them shows up in Firefox.
What's your experience? (tell me your OS, browser, their versions, and whether you have installed special fonts yourself.)
Python script to generate thumbnails from inline image links in HTML files. https://github.com/xahlee/xah_generate_thumbnail
A personal script. Now dumping to github.
The script is used to generate thumbnails for my gallery pages, e.g.
A Perl lib that emulates 30 list/tree manipulation functions in Mathematica. Tree::Matica Perl module
been thinking of reviving the project and port it to Python, Ruby. You are welcome to do so!
What Happens When You Name Your Functions/Variables as Math Symbols? See new section at bottom: Programing Style: Variable Naming: English Words Considered Harmful (programing practice; computer language design)
sending a lot resume out today Xah Lee's Resume. If you know some company looking, please help spread!
part of the problem of lambda in Python is this:
syntactically, lambda is a way to define a function, which may be arbitrarily complex. But due to Python syntax choice of indentation, so full lambda will need indentation, and thus cannot be a inline argument to other functions.
the other issue is that Guido doesn't like functional programing.
so, the take-away of this is that, syntax is fundamental in programing languages, as i have always advocated. And, syntax is the MOST important part of language. It influences thought and what sort of program comes out.
One of the tenets of Scheme is that there's only one way to name things. It's very non-Schemey to say that there are identifiers that are used for functions and there are identifiers that are used for data structures and there are identifiers used for processes or whatever it is. The whole point in Scheme is that this is one uniform way to refer to things. At the end of the day they're all procedures. They're all objects.
…
You have to contend with Python's broken notion of lambda but other than that it's not really that different.
From 〔Hal Abelson Q＆A By Peter Seibel. @ www.codequarterly.com…〕
python's broken lambda… Indeed.
“lisp-1 vs lisp-2”? One of the things that lispers forever ado about.
perm home: Xah's Perl ＆ Python ＆ Ruby Tutorial
Recently updated: linux man page tips: Linux: man page Tutorial
new: Ruby: Predefined Variables
See the bottom of the file for some Ruby quirks.
Ruby's predefined var is similar to Perl. In Perl, you can see the doc of them all by perldoc perlvar. But for Ruby, i haven't been able to find doc of these. Looks like it's not really documented.
Addedd Ruby. Python, Ruby, Perl: Formatting Strings
