$ time ./countlargenumber.pl
500000000500000000
real 0m43.157s
user 0m43.013s
sys 0m0.019sExecutable written in C counting from 1 to 1,000,000,000:
$ time ./countlargenumber.out
500000000500000000
real 0m2.057s
user 0m2.028s
sys 0m0.002s
Sunday, January 31, 2016
Duration of execution: Comparison Between Perl & C
Perl script counting from 1 to 1,000,000,000:
Executable written in C counting from 1 to 1,000,000,000:
Executable written in C counting from 1 to 1,000,000,000:
AWK: Extracting the Values of Specified Columns Separated by a Delimiter
Extracting the second column values from lines with delimiter '|' separating each columns:
awk -F'|' '{print $2}' ./lines.txt
Women's rights: Free the Nipple?
 |
| Gender equality |
- Gender equality (男女同権)
- Women's rights
- Social equality
MD5: Testing Out MD5 Behaviour
MD5 hash using s option:
MD5 hash using pipe:
MD5 hash using pipe, but echo without n option:
md5 -s "test string"
MD5 ("test string") = 6f8db599de986fab7a21625b7916589cMD5 hash using pipe:
echo -n test string | md5
6f8db599de986fab7a21625b7916589cMD5 hash using pipe, but echo without n option:
echo test string | md5
f299060e0383392ebeac64b714eca7e3
Sed: Replacing Delimiter Characters to Create Comma-Separated Values
Replacing all vertical lines '|' with comma ',':
cat ./lines.txt | sed s/\|/,/g
Saturday, January 30, 2016
AWK: Appending Characters to Each Line
Appending '|' character to the end of each lines:
awk '{print $0"|"}' ./input.txt > ./output.txt
Debugging: Cron: % sign
Error message:
The source code:
Crontab man page:
Fixed source code:
/bin/sh: -c: line 0: unexpected EOF while looking for matching `]'
/bin/sh: -c: line 1: syntax error: unexpected end of fileThe source code:
*/10 * * * * perl -le 'sleep rand 60' && head -$[${RANDOM} % `wc -l < /Users/username/lines.txt` + 1] /Users/username/lines.txt | tail -1 | ruby /Users/username/tweet.rbCrontab man page:
The entire command portion of the line, up to a newline or % character, will be executed by /bin/sh or by the shell specified in the SHELL variable of the cronfile. Percent-signs (%) in the command, unless escaped with backslash (\), will be changed into newline characters, and all data after the first % will be sent to the command as standard input.
Fixed source code:
*/10 * * * * perl -le 'sleep rand 60' && head -$[${RANDOM} \% `wc -l < /Users/username/lines.txt` + 1] /Users/username/lines.txt | tail -1 | ruby /Users/username/tweet.rbFriday, January 29, 2016
Cron: Tweet a Line Every 10-19 Minutes
Cron - Tweet a line every 30-40 mins:
lines.rb - using standard input:
*/10 * * * * perl -le 'sleep rand 540' && head -$[${RANDOM} \% `wc -l < /Users/username/lines.txt` + 1] /Users/username/lines.txt | tail -1 | ruby /Users/username/lines.rblines.rb - using standard input:
require 'json'
require 'oauth'
consumer_key = ''
consumer_secret = ''
access_token = ''
access_token_secret = ''
consumer = OAuth::Consumer.new(
consumer_key,
consumer_secret,
site:'https://api.twitter.com/'
)
endpoint = OAuth::AccessToken.new(consumer, access_token, access_token_secret)
# STATUS
status = STDIN.gets
# POST
response = endpoint.post('https://api.twitter.com/1.1/statuses/update.json', status: status )
result = JSON.parse(response.body)
Getting Random Line Number -1
Bash line to generate random line number from 1 to max - 1.
echo $(ruby -e 'print rand') $(wc -l < "./lines.txt") | awk '{printf("%d\n", $1*$2)}'African American Inventors
 |
| Henry E. Baker |
 |
| Benjamin Banneker |
 |
| James Forten |
 |
| Ben Montgomery |
 |
| Norbert Rillieux |
 |
| Jan Ernst Matzeliger |
 |
| Elijah McCoy |
 |
| George Franklin Grant |
 |
| Lewis Howard Latimer |
 |
| Granville Woods |
 |
| Garrett Morgan |
 |
| George Washington Carver |
 |
| Madam C. J. Walker |
 |
| Sarah E. Goode |
 |
| Sarah Boone |
 |
| Alice H. Parker |
 |
| Patricia Bath |
Thursday, January 28, 2016
Ruby: Tweeting Using OAuth gem
Package needed:
Ruby script: tweet.rb
Execute the ruby script:
gem install oauthRuby script: tweet.rb
require 'json'
require 'oauth'
consumer_key = '' # Your consumer key
consumer_secret = '' # Your consumer secret
access_token = '' # Your access token
access_token_secret = '' # Your access token secret
consumer = OAuth::Consumer.new(
consumer_key,
consumer_secret,
site:'https://api.twitter.com/'
)
endpoint = OAuth::AccessToken.new(consumer, access_token, access_token_secret)
# STATUS
status = ARGV[0]
# POST
response = endpoint.post('https://api.twitter.com/1.1/statuses/update.json', status: status )
result = JSON.parse(response.body)Execute the ruby script:
ruby ./tweet.rb "Good morning! (おはようございます。)"
Generating Random Password
Generating 32-character random password
This is the same:
$ cat /dev/urandom | env LC_CTYPE=C tr -dc 'a-zA-Z0-9' | fold -w 32 | head -n 1
This is the same:
$ cat /dev/urandom | env LC_CTYPE=C tr -dc '[:alnum:]' | fold -w 32 | head -n 1
Generating Random 15-Character User Name
Generating random 15-character:
$ cat /dev/urandom | env LC_CTYPE=C tr -dc 'a-z0-9' | fold -w 15 | head -n 1
This is the same:
$ $ cat /dev/urandom | env LC_CTYPE=C tr -cd '[:lower:][:digit:]' | fold -w 15 | head -n 1
Wednesday, January 27, 2016
Swift: Adding Sample to Health Store
 |
| Swift |
@IBAction func addPotassiumTapped(sender : AnyObject){
let potassiumType = HKQuantityType.quantityTypeForIdentifier(HKQuantityTypeIdentifierDietaryPotassium)
let potassiumQuantity = HKQuantity(unit: HKUnit.gramUnit(), doubleValue: 0.0055)
let potassiumSample = HKQuantitySample(type: potassiumType!, quantity: potassiumQuantity, startDate: NSDate(), endDate: NSDate())
let healthKitStore:HKHealthStore = HKHealthStore()
healthKitStore.saveObject(potassiumSample, withCompletion: { (success, error) -> Void in
if( error != nil ) {
print("Error saving Potassium sample: \(error!.localizedDescription)")
} else {
print("Potassium sample saved successfully!")
}
})
}
Tuesday, January 26, 2016
Swift: Request Authorization to Dietary Potassium Data
 |
| Swift |
@IBOutlet weak var aButton: UIButton!
@IBAction func buttonTapped(sender : AnyObject){
let healthKitStore:HKHealthStore = HKHealthStore()
let healthKitTypesToWrite = Set(
arrayLiteral: HKObjectType.quantityTypeForIdentifier(HKQuantityTypeIdentifierDietaryPotassium)! )
healthKitStore.requestAuthorizationToShareTypes(healthKitTypesToWrite, readTypes:nil){ (success, error) -> Void in
if success == false {
}
}
}
Swift: Display an alert
|
| Swift |
@IBOutlet weak var aButton: UIButton!
@IBAction func buttonTapped(sender : AnyObject){
let alertController = UIAlertController(title: "My alert", message:
"This is an alert!", preferredStyle: UIAlertControllerStyle.Alert)
alertController.addAction(UIAlertAction(title: "Dismiss", style: UIAlertActionStyle.Default,handler: nil))
self.presentViewController(alertController, animated: true, completion: nil)
}
Monday, January 25, 2016
Sunday, January 24, 2016
Saturday, January 23, 2016
Jacqueline Goordial: Nearing the cold-arid limits of microbial life in permafrost of an upper dry valley, Antarctica
 |
| Jacqueline Goordial |
Some of the coldest and driest permafrost soils on Earth are located in the high-elevation McMurdo Dry Valleys (MDVs) of Antarctica, but little is known about the permafrost microbial communities other than that microorganisms are present in these valleys. Here, we describe the microbiology and habitable conditions of highly unique dry and ice-cemented permafrost in University Valley, one of the coldest and driest regions in the MDVs (1700 m above sea level; mean temperature −23 °C; no degree days above freezing), where the ice in permafrost originates from vapour deposition rather than liquid water. We found that culturable and total microbial biomass in University Valley was extremely low, and microbial activity under ambient conditions was undetectable. Our results contrast with reports from the lower-elevation Dry Valleys and Arctic permafrost soils where active microbial populations are found, suggesting that the combination of severe cold, aridity, oligotrophy of University Valley permafrost soils severely limit microbial activity and survival.http://www.nature.com/ismej/journal/vaop/ncurrent/full/ismej2015239a.html
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