jemnotesversion 2 / showing all 180 or see latest only

defaults write com.apple.screencapture disable-shadow -bool true
killall SystemUIServer

defaults delete com.apple.screencapture disable-shadow
killall SystemUIServer

ssh remote-machine 'cat >> .ssh/authorized_keys' < .ssh/identity.pub

ssh -t reachable_host ssh unreachable_host

class String
  def brackets_match?
    stack = []
    each_char do |c|
      case c
      when '(', '[', '{'
        stack << c
      when ')'
        return false unless stack.pop == '('
      when '}'
        return false unless stack.pop == '{'
      when ']'
        return false unless stack.pop == '['
      end
    end
    stack.empty?
  end
end

should 'test matching brackets' do
  assert '(this)'.brackets_match?
  assert '(this)(fine)'.brackets_match?
  assert '(this)(fine)'.brackets_match?
  assert '[this][fine]'.brackets_match?
  assert '(this){fine}'.brackets_match?
  assert '(thi(s)){fine}'.brackets_match?

  refute '(thi(s)((fine)'.brackets_match?
  refute '{this){fine}'.brackets_match?
  refute '{this)(fine}'.brackets_match?
  refute '{this)(fine}'.brackets_match?
end

git fetch origin demo:demo

class Error404 < StandardError
end

class ApplicationController < ActionController::Base
  rescue_from Error404, with: :render_404

  def render_404
    respond_to do |format|
      format.html{render file: "#{RAILS_ROOT}/public/404.html", status: 404}
      format.all{render nothing: true, status: 404}
    end
    true
  end

  # etc.
end

raise Error404

render_404 and return

# Inside config/environment.rb:
require 'memcache'
CACHE = MemCache.new '127.0.0.1'

# A helper method:
def data_cache key
  unless output = CACHE.get(key)
    output = yield
    CACHE.set key, output, 1.hour
  end
  output
end

# When using it:
data_cache 'tag' do
  thing_to_cache
end

$DEBUG = true

puts false or true   # interpreted as puts(false) or true
=> false
puts false || true   # interpreted as puts(false || true)
=> true

sudo defaults write /Library/Preferences/SystemConfiguration/com.apple.Boot \
  'Kernel Flags' 'arch=x86_64'

git checkout --theirs filename
# or
git checkout --ours filename
# or, for an interactive interface
git mergetool

alias_method :new_name, :old_name

alias new_name old_name

(rdb:1) b app/controllers/my_controller.rb:10

# Copy three separate files on host to tmp.
rsync -av host:'file1 file2 file3' /tmp/

# Copy one file from host to tmp. ? matches any character.
rsync -av host:a?long?filename /tmp/
rsync -av host:'"a long filename"' /tmp/
rsync -av host:'a\ long\ filename' /tmp/
rsync -av host:a\\\ long\\\ filename /tmp/

git submodule add /path/to/remote local_name

git clone /path/to/repo-with-submod
cd repo-with-submod
git submodule init
git submodule update

class Widget < ActiveRecord::Base
  def errors
    [1,2]
  end
end

wdgt = Widget.new
wdgt.save!

NoMethodError (undefined method `full_messages' for #<Array:0x00000102344c68>)

\verb|{|    % nice, real brace.
{\tt \{}    % hideously replaced by sans-serif glyph.

\usepackage[T1]{fontenc}
% or
{\tt {\char '173} }

Dir.glob 'dir/*'
Dir.glob 'dir/*.rb'

set fo-=o

serialize attr_name, class_name=Object

gem install mongrel --source http://gems.rubyinstaller.org

script/plugin install git://github.com/tra/spawn.git

spawn do
  # job running in the background
end

xset b off

ls -R filename

<blah blah blah>: no such file to load -- net/https (RuntimeError)

def func()
  # Do something.
  ...

import cloud
cloud.call(func)

require 'chronic'

Time.now   #=> Sun Aug 27 23:18:25 PDT 2006

Chronic.parse('tomorrow')
  #=> Mon Aug 28 12:00:00 PDT 2006

Chronic.parse('monday', :context => :past)
  #=> Mon Aug 21 12:00:00 PDT 2006

Chronic.parse('this tuesday 5:00')
  #=> Tue Aug 29 17:00:00 PDT 2006

Chronic.parse('this tuesday 5:00', :ambiguous_time_range => :none)
  #=> Tue Aug 29 05:00:00 PDT 2006

Chronic.parse('may 27th', :now => Time.local(2000, 1, 1))
  #=> Sat May 27 12:00:00 PDT 2000

Chronic.parse('may 27th', :guess => false)
  #=> Sun May 27 00:00:00 PDT 2007..Mon May 28 00:00:00 PDT 2007

javascript:document.body.contentEditable='true'; document.designMode='on'; void 0

yl/<C-R>"

\newcommand{\err}[1]{\textcolor{red}{#1}}

nm ./bin/maci/libeng.dylib

git checkout sha1 filename

git show sha1 filename

git show sha1:filename

> git checkout sha1:filename
fatal: reference is not a tree: sha1:filename

% Same as a = x, b = y, c = z:
[a, b, c] = deal(x, y, z);

:g/.*/m0

FileUtils.mkdir_p '/tmp/a/b/c/d/e/'

>> [1.14, 1.15, 1.16].map{|x| "%.1f" % x}
=> ["1.1", "1.1", "1.2"]
>> [1.4, 1.5, 1.6].map{|x| "%.0f" % x}
=> ["1", "2", "2"]

> gem1.9 which haml
(checking gem haml-2.2.15 for haml)
/usr/local/lib/ruby1.9/gems/1.9.1/gems/haml-2.2.15/lib/haml.rb

def freq_table(a)
  d = {}
  d.default = 0
  a.each{|x| d[x] += 1}
  d
end

class String
  def valid_float?
    true if Float self rescue false
  end
end

require 'rubygems'
require 'rmov'

# locs refers to the filename of the original files.
locs = [2732, 2734, 2736, 2739, 2740, 2744, 2746, 2748, 2749]
offsets = [41.12, 4.25, 1.8, 0.0, 0.8, 2.5, 1.65, 4.7, 0.8]

clips = []
locs.zip(offsets).each do |l,off|
  filename = "source/MVI_#{l}/MVI_#{l} - iPhone.m4v"
  clips << QuickTime::Movie.open(filename)
  clips.last.delete_section 0, off
end

background = QuickTime::Movie.open 'source/background_480x360.png'

q = QuickTime::Movie.empty
length = clips.map(&:duration).max.ceil
puts length
(length*15).times do
  q.insert_movie background, 0
end

WIDTH = 480
HEIGHT = 360

clips.each_with_index do |c,i|
  row = i / 3
  col = i % 3

  q.composite_movie c, 0

  a = q.tracks[-1]
  a.scale 0.34, 0.34
  a.translate col*WIDTH/3, row*HEIGHT/3
end

exporter = q.exporter
if File.exist? 'settings.st'
  exporter.load_settings 'settings.st'
else
  exporter.open_settings_dialog
  exporter.save_settings 'settings.st'
end

outname = "output.mov"
puts "creating #{outname}."
exporter.export outname do |progress|
  percent = (progress*100).round
  puts "#{percent}% complete"
end

sudo vim /etc/apache2/users/username.conf
# add FollowSymLinks.
sudo apachectl graceful

git diff HEAD^ file  # shows differences between previous and current version of file.

git show HEAD^ file  # WRONG: prints a blank line. No messages, no warnings.
git show HEAD^:file  # RIGHT: (note colon) shows the previous version of file.

server = TCPServer.new '127.0.0.1', 0
port = server.addr[1]

arch -i386 irb

script/console --irb=irb1.9

:+s/searchtext
:+s/searchtext//

# Both lines will produce the same output, but the first is a variable.
echo ~+
pwd

require 'enumerator'

cd -                  # go back to previous directory.
pushd /new/directory  # go to new dir; add current dir to stack.
popd                  # retrieve dir from stack; go there.

gem install relevance-rcov --source http://gems.github.com

curl -O http://example.com/file.sty
# equivalent to
wget http://example.com/file.sty

convert -density 300x300 -resize 1000x1000 infile.pdf outfile.png

sudo scutil --set HostName servername.example.com

git config branch.master.remote origin
git config branch.master.merge refs/heads/master

# Python version.
prod = 1
for x in range(1, 10):
    prod *= x
prod

# Ruby version.
(1..9).inject :*

x = ('a'..'z').to_enum
y = (1..10).to_enum
loop do
  puts "#{x.next}: #{y.next}"
end

begin
  # Load wirble
  require 'rubygems'
  require 'wirble'

  # Start wirble (with color)
  Wirble.init
  Wirble.colorize
rescue LoadError => err
  warn "Couldn't load Wirble: #{err}"
end

IO.read('image.png')[0x10..0x18].unpack('NN')

# Same as ['symmetric', 'matrix', 'vector', 'scalar']:
%w{symmetric matrix vector scalar}

Last login: Thu May 21 23:31:00 2009

touch .hushlogin

Line #      Hits         Time  Per Hit   + Time  Line Contents
==============================================================
...
202      1741        12946      7.4      0.0      for k in zip(K.I, K.J):
203      1740       222659    128.0      0.9          K[k] = randn()
...

for index, item in enumerate(items):
    pass

inoremap # a#<Left><BS><Right>

l = []
def app():
  l += (1,)
app()

# On the server, to avoid having copies of local files.
git --bare init 

# On the client.
git remote add origin ssh://hostname/path/to/repo
git push origin master

git reset --soft HEAD^

git config --global core.excludesfile ~/.gitignore

$('li:visible:not(:has(img.checkmark.checked))').hide('slow')

# Basic version.
print 'My name is +s and I am +d.' + (p.name, p.age)
# Advanced version.
print 'My name is +(name)s and I am +(age)d.' + p.__dict__

{}{py}
for (index, item) in enumerate(items):
    print index, item

# Naive piece of code.
for (cat, amount) in data:
    if cat not in d:
        d[cat] = 0
    d[cat] += amount

# Simpler piece of code.
for (cat, amount) in data:
    d.setdefault(cat, 0)
    d[cat] += amount

# A cunning third option: setdefault also gets.
for (cat, amount) in data:
    d[cat] = d.setdefault(cat, 0) + amount

from collections import defaultdict
d = defaultdict(generator_function)

# Example like those above.
d = defaultdict(lambda: 0)

sum(i**2 for i in xrange(1e5))

# fine.
assert expr1, expr2

# WRONG!
assert(expr1, expr2)

git log -p filename

git show HEAD^:filename

dseditgroup -o create -i 499 groupname
dseditgroup -o edit -a username groupname

class FifoDict(object):
    def __init__(self, maxentries=100):
        self.lastentries = []
        self.mydict = {}
        self.maxentries = maxentries

    def __getitem__(self, k):
        return self.mydict[k]

    def __setitem__(self, k, val):
        if len(self.lastentries) >= self.maxentries:
            del self.mydict[self.lastentries.pop()]
        self.mydict[k] = val
        self.lastentries.insert(0, k)

    def __str__(self):
        return str(self.mydict)

    def __repr__(self):
        return repr(self.mydict)

for FILE in one* ; do mv $FILE `echo $FILE | sed 's/one//'` ; done

rename 's/^one//' one*

sudo easy_install ipython
sudo easy_install -f http://ipython.scipy.org/dist/ readline

> ulimit -a
core file size          (blocks, -c) 0
data seg size           (kbytes, -d) 6144
file size               (blocks, -f) unlimited
max locked memory       (kbytes, -l) unlimited
max memory size         (kbytes, -m) unlimited
open files                      (-n) 256
pipe size            (512 bytes, -p) 1
stack size              (kbytes, -s) 8192
cpu time               (seconds, -t) unlimited
max user processes              (-u) 266
virtual memory          (kbytes, -v) unlimited

passwd -e username

sudo ifconfig lo0 alias 127.0.0.2 up

sudo ssh -N -L 127.0.0.2:139:localhost:139 -L 127.0.0.2:445:localhost:445 user@server.com

# Check memory accesses.
valgrind --tool=memcheck ./prog

# View cache and branch profiling information.
valgrind --tool=cachegrind ./prog

autocmd Filetype tex syntax clear texOnlyMath

>>> import pylab
>>> print pylab
<module 'pylab' from '/usr/lib/python2.5/site-packages/pylab.pyc'>

> python -m cProfile -o outprof.tmp examples/bb30.py

>>> import pstats
>>> p = pstats.Stats('outprof.tmp')
>>> p.strip_dirs().sort_stats('cumulative').print_stats(50)

./prog | tee >(gzip > logfile.tgz)

gs -dBATCH -dNOPAUSE -dNOPROMPT -sDEVICE=epswrite -sOutputFile=new.eps old.pdf

find . -name 'Makefile' -exec sed -i -e 's/4\.3/4.4/g' {} \;

# Next command on a single line.
alias lr='latex -file-line-error-style -interaction=nonstopmode $LR.tex > 
  /tmp/latexoutput || cat /tmp/latexoutput ; 
  grep -e "\(LaTeX Warning\)\|\(Overfull\)\|\(Underfull\)" /tmp/latexoutput | 
  grep -v "There were undefined references";
  killall -SIGUSR1 xdvi.bin 2> /dev/null'

alias xdj='xdvi -paper us -expert -keep $LR.dvi 2>/dev/null >/dev/null&'

>> LR=myfilename # set filename. The suffix .tex is added automatically.
>> lr            # compiles your latex document.
>> xdj           # displays your latex document.

gcc -c -g -Wa,-ahl src.c

gcc -dM -E - < /dev/null

min(find(rand() < cumsum(p)))

>> 1 / [1 2 3]' 
ans =
         0         0    0.3333

A / B = (B^T \backslash A^T)^T,

    / = \backslash^T.

find . -name '*.sw*' -print

find . -name "*.bib" -exec echo {}; grep "tribute to" '{}'

>> gcc -c -Q -Os --help=optimizers
The following options control optimizations:
  -falign-jumps                         [disabled]
  -falign-labels                        [disabled]
  -falign-loops                         [enabled]
# ...
  -fwhole-program                       [disabled]
  -fwrapv                               [disabled]

#include <time.h>
static clock_t tic_timestart;

void tic(void) {
   tic_timestart = clock();
}

float toc(void) {
   clock_t tic_timestop;
   tic_timestop = clock();
   printf("time: %8.2f.\n", (float)(tic_timestop - tic_timestart) / CLOCKS_PER_SEC);
   return (float)(tic_timestop - tic_timestart) / CLOCKS_PER_SEC;
}

float tocq(void) {
   clock_t tic_timestop;
   tic_timestop = clock();
   return (float)(tic_timestop - tic_timestart) / CLOCKS_PER_SEC;
}

/* CFDIV    divides             1/a[3]
* CFADD    adds                c[12] + d[12]
* CFMUL    multiplies          b[4] * h[7]
* CFASN    assigns             A[5] = 0
* CFSTO    stores              A[5] = (...)
* CFTFR    transfers           A[5] = b[7]
* CFNTF    negated transfers   A[5] = -b[7]
* CFCOM    compares            c[5] < b[7]
*/
typedef struct statistics_t *statistics;
typedef struct statistics_t {
   long div;
   long add;
   long mul;
   long asn;
   long sto;
   long tfr;
   long ntf;
   long com;
} Statistics;