Xah's Programing Blog

How to set git output non-interactive?

git log > z

How to make git display date in ISO format?

git log --date=iso > z

See also: git Tutorial

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.

Syntax = Most Important Aspect of a Programing Language

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)

One Thousand Function Keys, Redux

A new function keys keyboard manufacture. See: http://www.access-is.com/custom_keyboards.php

that's nice if you are the master of function keys. See also:

• Keyboard Master: One Thousand Function Keys
• Computer Keyboard: Increase Productivity Using Function Keys
• Keyboard Shortcut Design: Dedicated keys, Special Buttons, Extra Keys
• A Curious Look at GNU Emacs's 1000+ Default Keybinding

thx to David Rogoff

Linux: Convert HTML to PDF

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…〗.

Writing grep/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

Emacs: new major modes for HTML, CSS, PHP, ELISP, and Lean Emacs LISP Manual

Vote which one you want me to work on. Tell your friends please. http://pledgie.com/campaigns/19973

more fancy keyboards

one of my article hit Hacker News. https://news.ycombinator.com/item?id=5517593

What Does it Means When a Programing Language Claims “Whitespace is Insignificant”?

3 articles on the statet of the onion. Perl is not dead, but is dead end.

〔Texinfo 5.0 in Perl 2013-02-19 By Dave Cross. @ perlhacks.com…〕

〔Perl is not Dead, it is a Dead End 2013-01-12 By Stevan Little. @ speakerdeck.com…〕

〔Goodnight, Parrot 2013-02-09 By Chromatic. @ www.modernperlbooks.com…〕

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.

lol. Perl added a say in v5.10 2007-12-18. 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 should it be post-post-modern Perl?

learned a new Linux command: watch. ⁖ watch ls.

this is useful when you want to run some command regularly and itself doesn't have auto-update.

thx to Ryuutei Sebastien BLANC

see also Linux: Most Frequently Used Shell Commands

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, short 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.

Unicode Symbols for Alt Key and Control Key

recently discovered proper symbol for the Alt key, and few others. Example:

• ⎇ Alt+x. ALTERNATIVE KEY SYMBOL⎇
• ⌥ Opt+x. OPTION KEY ⌥.
• ✲ Ctrl+x. OPEN CENTRE ASTERISK ✲. Printed on Microsoft keyboards. 〔☛ Microsoft Keyboards Gallery〕
• ⎈ Ctrl+x. HELM ⎈. Not sure where this is actually used, but on Linux 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 some annotation from ISO standard. Anyone knows?)
• ⎋ Esc. BROKEN CIRCLE WITH NORTHWEST ARROW ⎋. Standard escape symbol.

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 ⌘ Cmd = ❖ 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 ↹ ⌫ ⌘ ✉ ✍ ⌖

Symbology

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 Gallery ＆ Tutorial ∑ ∞ π © ™ § ☺ ♀ ♂ ♥

Unicode 6 Font for Linux

Unicode 6 added over 2k chars. 600 of them are emoticons, and many others are icons, 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: 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.

JavaScript App for Unicode

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.

• Unicode: Transport ＆ Map Symbols ♿ ⚠ ⛽ ⛾
• Unicode Animal ＆ Insect Icons 🐭 🐮 🐍 🐵 🐞
• Unicode Office Icons
• Sports ＆ Games Icons ♤ ♧ ♡ ♢
• Astronomy Symbols ☿ ♁ ♆ ☾ 🌛 ♈ ♋
• Weather Symbols ☂ ☃ ⛅
• Unicode Music Symbols 𝄞 ♪ ♫ ♬ 🎹 🎸

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.