This cheatsheet has been moved to Obisidian for now. Don't make edits here!!!!! Cheatsheet for git, rails, unix etc.

activerecord-cheatsheet.md

Jsonb AR querying:

• All records where a particular key is present:

  Groupings::Collection.where("document ? 'name'")

  OR

  Groupings::Collection.where("document ? :key", {key: 'name'}).

• Search for records where document attribute is not null:

  Contents::Audio.s3.where("document->>'s3_file_path' IS NOT NULL")

• Article on jsonb querying: https://nandovieira.com/using-postgresql-and-jsonb-with-ruby-on-rails

• Query all records for a specific value stored in the jsonb column.

  Contents::Document.where("document ->> 'file_content_type' = ?", 'application/octet-stream')

  Helpful resource https://makandracards.com/makandra/37851-how-to-query-postgresql-s-json-fields-from-rails

browser-console.md

• Open load all github files that are not loaded.

document.querySelectorAll('.load-diff-button').forEach(node => node.click())

git-cheatsheet.md

Git

• Version of git

  git --version

• View user name and email for current user:

  git config user.name

  git config user.email

• Change user name and email for current repository:

  git config user.name "Gagan"

  git config user.email "[email protected]"

• Change user name and email for all repositories:

  git config --global user.name "Gagan"

  git config --global user.email "[email protected]"

• Set the colors for git:

  git config --global color.ui true

• Set default pager for git

  #Default is less. Setting to '' will stop the use of pager
  git config --global core.pager ''
  

Remote

• Add a git remote:

  git remote add <remote-name> [email protected]

• Remove a git remote:

  git remote rm <remote-name>

• View git remotes: git remote -v

Pulling, adding, committing and related commands

• To add the same file in patches, so that they can be committed under different commits:

  git add filename -p

• To stage all the files that are delete locally:

  git rm $(git ls-files --deleted)

• To see the difference of files that are staged

  git diff --cached or git diff --staged

• To see more context than just 3 lines in a git diff

  git diff -U7

• To change your last commit message do

  git commit --amend

• To push from a branch to github do

  git push origin <local-branchname>(:<remote-branchname>)

• Dry run your push

  git push --dry-run origin <local-branchname>(:<remote-branchname>)

  It is often better to test out what changes will happen with you push. The options to use to do that is --dry-run

Listing files

• deleted files:

  git ls-files --deleted

• all untracked files:

  git ls-files -o

• all files that git has ignored:

  git ls-files --exclude-standard

• untracked files that git doesn't ignore (i.e. all new files):

  git ls-files --other --exclude-standard

• Files that match a pattern:

  git ls-files vendor*

• Removing ignored file from the repository:

  To delete a file from the repository but keep it in your working directory (this might come in handy when the file has been ignored)

  git rm --cached <file>

Clean

Remove untracked files dry run: git clean -n

clean untacked files

git clean -f

OR rm -r $(git ls-files --other --exclude-standard)

clean untracked files and directories

git clean -f -d

git clean untraced files including ignored files

git clean -f -x

options -d removes directory -n dry-run, -f force, -x remove files ignored by .gitignore

Reverting

• To revert changes done to a particular file in a particular commit you can use the command.

  git checkout <sha-of-commit> <path-to-file>

Checkout

• When in the middle of conflict while merging branches

  And you want to keep the changes in a file as the were in the trunk:

  git checkout --ours index.html

  or you want to keep changes in a file as they were in the branch:

  git checkout --theirs layouts/default.html

tagging

• Adding a tag git tag -a '<tag-number>' -m 'tag-message'

• push all tags git push --tags

• delete tag locally git tag -d <tag-number>

• delete a tag in the repository that has been remove locally git push origin :refs/tags/<tag-number>

• add a tag to the sha git tag <tag-number> <sha-of-commit> -m "message of tag"

branching & merging

• To see all branches including all branches (ie local and remote):

  git branch -a

• To create a new branch from a particular commit that exists in the log of current branch

  git branch branchname sha-of-commit

• Delete a branch in repository that is deleted locally

  git push origin :feature/sass i.e. add colon before the branch name

• Create a branch from a previous commit: git branch branchname <sha1-of-commit>

• List existing remote branches: git ls-remote --heads

• Use a mergetool to help resolve conflicts git mergetool

gui

• Git's Graphical user interface git gui

bisect

• Find the commit that introduces a bug using git bisect. See http://robots.thoughtbot.com/git-bisect git bisect start

  git bisect good <sha-of-good-commit>

  git bisect bad <sha-of-bad-commit>

  git bisect run rspec spec/features/my_broken_spec.rb #To automate the bisect feature.

Log

• To view recent commit on the current branch with each commit on one line git log --pretty=oneline

  git ref log

• View changes in one branch that do not exist in the other git log branch1 --not branch2

• You can use the -- option in git log to see the commit history for a file, even if you have deleted the file git log -- [file_path]

  See http://www.vogella.com/tutorials/Git/article.html#retrievefiles_finddeletedfile

  You can use the above to find the commit which deleted a file and the browse the code at that commit in github.

heroku-cheatsheet.md

Heroku:

• To push develop to heroku

  git push heroku develop:master

• Add a remote to heroku repo url

  heroku git:remote -a appname

• Get a local dump for a pg database on heroku:

  curl -o latest.dump $(heroku pgbackups:url)

• Get pgbackup url

  heroku pgbackups:url

• Restore pg database from a url:

  • NOTE: If you are going to restore a whole database from a dump, it makes sense to first clobber the existing one using heroku pg:reset. You can potentially hit some migratino problems otherwise.

  heroku pgbackups:restore CRIMSON 'http://s3.url.com' --remote staging

• To drop / reset the database

  heroku pg:reset DATABASE

• Deleting precompiled assets to force all assets to get precompiled again

  heroku repo:purge_cache -a <appname>

  • you need the heroku repo plugin to do that

• If you have the following errors when pushing to heroku:

  error: RPC failed; HTTP 500 curl 22 The requested URL returned error: 500 Internal Server Error
  

  use heroku repo:reset -a <appname>

• See running sql statements on the database:

  heroku pg:ps --app dg-api-production

node-cheatsheet.md

Node and npm

• Upgrading npm

  [sudo] npm i -g npm

• To make sure my local npm files are in alignment with the the files in the respository:

  npm i -g npm
  rm -rf node_modules/
  npm i
  

  • To install a package to a specific version and update package.json and package-lock.json see following example:

    npm install [email protected]
  

  Learn more about --save and --save-dev to make updates locally to node_modules when running the aforementioned command.

  • Audit security issues:

  npm audit
  

  To fix security issues use

  npm audit fix
  

  • Running eslint I had trouble running eslint using npm run eslint. I also had trouble runniing it with ./node_modules//bin/eslint . .

  I had to run it using ./node_modules/bin/eslint app/ --ext es6.

3k3:3

postgresql.md

• Listing all tables

  \d

• Listing all users

  \du OR \du+

  The use of + adds a description of every user. You can also list users by querying the pg_catalog.pg_user table.

pry-cheatsheet.md

PRY

• ls (list methods) in self
• ls —grep finds specific names
• cd <object> cds into the object... ie that is the new self.
• ? (show-doc) Class#method / object.method
• $ (show-method) Class#method / object.method
• next (next line without stepping through function calls)
• step (next line respecting function call)
• play -l 6 (play line number 6... same as copyig and pasting that line)
• edit (opens up the editor to edit the file) / edit -m (edit current method)
• edit <method> edits the specific method
• try-again (I think that is a part of pry-rescue which re-runs the specific failing? test or rails request)
• break <method> break on the method
• break -d 1 disable first breakpoint.
• up / down (go and and down the call stack)
• whereami (get information on where you are in the call stack)
• _ex_ recently raised exception
• _file_ (last required file)
• binding.pry open pry within the current binding
• _ex_.bractrace gives backtrace of the exception
• wtf gives first five lines of the backtrace
• wtf??? with increasing question marks gives increasing lines of backtrace.
• exit-program exit all future breakpoints and the current running process.

rails-cheetsheet.md

Bundler

• Find inverse dependencies of a gem gem dependency <gemname> --reverse-dependencie

• Edit installed gem in bundler

  export BUNDLER_EDITOR=mvim && bundle open gemname

• List out all the gems that will be updated if you run the bundle update command: bundle outdated

• clean out all the unrequired gems under certain conditions.

  bundle clean

To read more about it you can try:  http://patshaughnessy.net/2011/11/5/besides-being-faster-what-else-is-new-in-bundler-1-1

Rake

• List all possible rake tasks rake -T

• To see routes: bundle exec rake routes

• To list all the middleware bundle exec rake middleware

Rails

• Start the rails server with debugger options

  rails server --debugger

• To test out some code without changing any data:

  rails console --sandbox Any modifications that are made will be rolled back on exit.

Rails Generators

igrations:

• To migrate:

  rake db:migrate

• To go back one migration:

  rake db:rollback

• To go back two migrations:

  rake db:rollback STEP=2

• Adding a column

  rails generate migration AddActiveToNews active:boolean

• Adding paperclip columns:

  rails generate migration add_paperclip_columns_to_my_model image_file_name:string image_content_type:string image_file_size:integer image_updated_at:datetime

• Mailers:

To automatically generate mailer and associated directories

rails generate mailer MyMailer

RubyGems

• Create a gem executible gem build scriptura.gemspec
• Publish a gem gem push <gem-file-name example gem push scriptura-0.0.3.gem

HTTParty

• Making an Http get request using tokens:

   HTTParty.get("http://api.local.dg:3000/v0/collections/wjfmvjzo/resources", :query => {"page[number]" => '1', "page[size]" => '366'}, :headers => {'Authorization' => "Token token=\"api-token\""})
  

Local bootstrap:
Use: FILE=/Users/gagan/projects/desiring-god-new/db/dumps/dg_production_a926_20161228T103557-0600.dump rake db:bootstrap

RVM

• To get the information about all possibilities of using the rvm command:

  rvm

• To see a list of installed rubies:

  rvm list; #My terminal does not show the system installed ruby with this command

• To go to the system installed version of rvm

  rvm system

• To make system version of ruby default ,

  rvm system --default

• to uninstall rvm

  rvm implode apparently

unix-cheatsheet.md

Unix

Grep

Excluding directories in your grep

When it is in the current directory:

grep -r -F "Date" . --exclude-dir={.git,tmp,log,vendor}

When it is in the tree but not the current directory

grep -r -F "Date" . --exclude="*spec/cassettes*"

Curl

Only get headers from the url

curl -s -D - https://www.desiringgod.org -o /dev/null

Only get headers from the url behind http digest auth

curl -s -D - http://staging.desiringgod.org -o /dev/null --digest -u <username>

Then enter password. or try:

curl -s -D - https://dgbeta.org -o /dev/null --digest -u <username>:<password>

Bash

Run command multiple times: for i in {1..10}; do commandNameHere; done http://www.cyberciti.biz/faq/bsd-appleosx-linux-bash-shell-run-command-n-times/

find and replace

find and replace recursively within a folder:

perl -p -i -e 's/oldstring/newstring/g' `find ./ -name '*.rb'` or

perl -p -i -e 's/oldstring/newstring/g' `grep -ril oldstring *`

Replace backreference with lower case:

• \l change the case
• \L also changes the case

Using a variable to replace existing matching expression

• Following script changes ResourceType.find('Article), or ResourceType.find('Books') to ResourceType.find('articles') ResourceType.find('books') perl -p -i -e "s/ResourceType.find\('(.)/ResourceType.find('\l\$1/g" spec/redirectors/v_2014/resource_library_spec.rb

• Following script replaces %r{<something>} to hello(<something>) in lib/scripts
perl -p -i -e "s/%r\{(.*)}/hello(\$1)/g" lib/scripts/

Looping

Repeat command multiple times over

for i in {1..10}; do rspec spec/features/resource_library/sermons_spec.rb; done

Renaming files in a pattern using unix

for f in *worker* ; do mv "$f" "echo $f | sed s/worker/job/"; done

Renaming files in a pattern using ruby

> folder_path = '/Users/gagan/projects/desiring-god-new/app/jobs'
> Dir.glob(folder_path + '/*').each do |f|
>     File.rename(f, folder_path + '/' + File.basename(f).gsub('worker', 'job') + File.extname(f))
> end

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