cheatsheets

cheatsheets.md

Dev Cheat Sheets

Personal collection of commands and snippets that just won't stay in my head.

git.md

Git

Branches

Search and delete multiple branches

git branch | grep '3\.2' | xargs git branch -d

Push to remote with different name

git push heroku develop:master

Others

git-flow epic infographic

openssl.md

OpenSSL

Certificates

MD5 hash of modulus from key/cert/csr

Usefull to identify if multiple certificates have been signed with the same key.

openssl x509 -noout -modulus -in certificate.crt | openssl md5
openssl rsa -noout -modulus -in privateKey.key | openssl md5
openssl req -noout -modulus -in CSR.csr | openssl md5

Certificate expiry date

openssl x509 -noout -in certificate.crt -dates

ops.md

DevOps

Vagrant

SSH as specific user

vagrant ssh -- -l deploy -i ~/.ssh/id_rsa

ruby.md

Ruby / Rails / RVM

RVM

Create .ruby-version and .ruby-gemset

rvm --ruby-version use 1.9.3@gemset-name

List all rubies and gemsets

rvm gemset list_all

List local gems

gem list --local

Remove rubygems

Handy on legacy projects using ancient versions of rubygems. rvm rubygems remove

Hash

Rename hash keys

Hash[ hash.map { |k,v| ["#{k}_something", v ] } ]

Time & Dates

String from time with format

Time.now.strftime('%Y/%m/%d')
=> "2014/08/11"

Snippets

Export array to CSV file

# Fetch data
a = User.active.map { |u| [u.name, u.email] }
# Transform data to CSV
csv = a.map { |e| e.join(', ') }.join("\n")
# Write to file
File.open("users.csv", "w") { |f| f.write(csv) }