francisco-rojas

Use http://rubular.com/ or https://jex.im/regulex/#!flags=&re=%5E(a%7Cb)*%3F%24 to test your regex.

#####Regex Basics

• [abc] A single character of: a, b, or c
• [^abc] Any single character except: a, b, or c
• [a-z] Any single character in the range a-z
• [a-zA-Z] Any single character in the range a-z or A-Z
• ^ Start of line
• $ End of line
• \A Start of string

francisco-rojas

Chapter 1: Driving Code Through Tests

retry and redo

redo and retry are both used to re-execute parts of a loop. But they differ in how much they re-execute: redo only repeats the current iteration, while retry repeats the whole loop from the start.

redo example:

(0..5).each do |i|

francisco-rojas

To avoid the logs growing too large logrotation can be configured with Linux's logrotate tool. The logrotation configuration file is located at: /etc/logrotate.d/your_app_name Example of logrotate configuration file for a Rails app (remember to remove the comments!):

# monitor the /home/deploy/path/to/my/app/shared/log/*.log file
/home/deploy/path/to/my/app/shared/log/*.log {
        weekly # rotate weekly
        missingok #  avoids halting on any error and carries on with the next log file
        rotate 52 # 52 days worth of logs would be kept
 compress # compress using gzip

francisco-rojas

###du Summarize disk usage of each FILE, recursively for directories sorted by size

sudo du -x -h / | sort -n | tail -40

###truncate Truncate files to size 0MB

truncate -s 0 production.log

francisco-rojas

Open Classes (also known as Monkey Patching)

Instead of creating a class that performs common operations on strings like this:

class StringUtils
  def self.to_alphanumeric(s)
    s.gsub(/[^\w\s]/, '')
  end
end