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Version: 1.0


Ruby is A dynamic, open source programming language with a focus on simplicity and productivity.


Change RubyGems repo

Sometimes, can't not access in China, or very slowly, you can RubyGems to Chinese mirror:

# check repo
gem sources -l

# delete repo
gem sources --remove

# install new repo
gem sources -a

# replace bundle repo
bundle config mirror.

Change Ruby version

You can use rvm to change Ruby version

Web Framework


Local computer browser to access Rails: http://Server's Internet IP:3000

Ruby Rails





Ruby install directory: /usr/local/rvm/rubies/ruby-version
Ruby bin directory: /usr/local/rvm/rubies/ruby-2.4.10/bin
RVM install directory: /usr/local/rvm

version is version number

Passenger install directory: /usr/lib/ruby/vendor_ruby/phusion_passenger
Passenger configuration file: /etc/apache2/mods-enabled/passenger.conf


ruby -v
bundler -v
gem -v
rails -v
passenger -v


sudo systemctl start | stop | restart | status rails
sudo systemctl start | stop | restart | status passenger



$ passenger -h


gem -h

RubyGems is a sophisticated package manager for Ruby. This is a
basic help message containing pointers to more information.

gem -h/--help
gem -v/--version
gem command [arguments...] [options...]

gem install rake
gem list --local
gem build package.gemspec
gem help install

Further help:
gem help commands list all 'gem' commands
gem help examples show some examples of usage
gem help gem_dependencies gem dependencies file guide
gem help platforms gem platforms guide
gem help <COMMAND> show help on COMMAND
(e.g. 'gem help install')
gem server present a web page at
with info about installed gems
Further information:


bundle -h

bundle outdated(1) bundle-outdated.1.html
Show all of the outdated gems in the current bundle

bundle console(1)
Start an IRB session in the current bundle

bundle open(1) bundle-open.1.html
Open an installed gem in the editor

bundle lock(1) bundle-lock.1.html
Generate a lockfile for your dependencies

bundle viz(1) bundle-viz.1.html
Generate a visual representation of your dependencies

bundle init(1) bundle-init.1.html
Generate a simple Gemfile, placed in the current directory

bundle gem(1) bundle-gem.1.html
Create a simple gem, suitable for development with Bundler

bundle platform(1) bundle-platform.1.html
Display platform compatibility information

bundle clean(1) bundle-clean.1.html
Clean up unused gems in your Bundler directory

bundle doctor(1) bundle-doctor.1.html
Display warnings about common problems

bundle remove(1) bundle-remove.1.html
Removes gems from the Gemfile

When running a command that isn´t listed in PRIMARY COMMANDS or UTILITIES, Bundler will try to find an executable on your path named bundler-<command> and execute it, passing down
any extra arguments to it.

These commands are obsolete and should no longer be used:

· bundle cache(1)

· bundle show(1)


$rvm -h

Warning! PATH is not properly set up, /usr/local/rvm/gems/ruby-2.4.10/bin is not at first place.
Usually this is caused by shell initialization files. Search for PATH=... entries.
You can also re-add RVM to your profile by running: rvm get stable --auto-dotfiles
To fix it temporarily in this shell session run: rvm use ruby-2.4.10
To ignore this error add rvm_silence_path_mismatch_check_flag=1 to your ~/.rvmrc file.
Ruby enVironment Manager 1.29.12 (latest) (c) 2009-2020 Michal Papis, Piotr Kuczynski, Wayne E. Seguin


rvm [--debug][--trace][--nice] <command> <options>

for example:

rvm list # list installed interpreters
rvm list known # list available interpreters
rvm install <version> # install ruby interpreter
rvm use <version> # switch to specified ruby interpreter
rvm remove <version> # remove ruby interpreter (alias: delete)
rvm get <version> # upgrade rvm: stable, master

Available commands:

rvm has a number of common commands, listed below. Additional information about any command
can be found by executing `rvm help <command>`.

ruby installation
fetch # download binary or sources for selected ruby version
install # install ruby interpreter
list # show currently installed ruby interpreters
list known # list available interpreters
mount # install ruby from external locations
patchset # tools related to managing ruby patchsets
pkg # install a dependency package
reinstall # reinstall ruby and run gem pristine on all gems
remove # remove ruby and downloaded sources (alias: delete)
requirements # installs dependencies for building ruby
uninstall # uninstall ruby, keeping it's sources
upgrade # upgrade to another ruby version, migrating gems

running different ruby versions
current # print current ruby version and name of used gemsets
do # runs a command against specified and/or all rubies
gemdir # display path to current gem directory ($GEM_HOME)
use <version> # switch to given (and already installed) ruby version
use default # switch to default ruby, or system if none is set
use system # switch to system ruby
wrapper # creates wrapper executables for a given ruby & gemset

managing gemsets
gemset # manage gemsets
migrate # migrate all gemsets from one ruby to another

rvm configuration
alias # define aliases for `rvm use`
autolibs # tweak settings for installing dependencies automatically
group # tools for managing groups in multiuser installations
rvmrc # tools related to managing .rvmrc trust & loading gemsets

rvm maintenance
implode # removes the rvm installation completely
cleanup # remove stale source files & data associated with rvm
cron # manage setup for using ruby in cron
docs # tools to make installing ri and rdoc docs easier
get # upgrades RVM to latest head, stable or branched version
osx-ssl-certs # helps update OpenSSL certs installed by rvm on OS X
reload # reload rvm source itself
reset # remove all default and system settings
snapshot # backup/restore rvm installation

config-get # display values for RbConfig::CONFIG variables
debug # additional information helping to discover issues
export # set temporary env variable in the current shell
fix-permissions # repairs broken permissions
repair # lets you repair parts of your environment, such as
# wrappers, env files and similar (general maintenance)
rubygems # switches version of rubygems for the current ruby
tools # general information about the ruby env
unexport # undo changes made to the environment by `rvm export`
user # tools for managing RVM mixed mode in multiuser installs

information and documentation
info # show the environment information for current ruby
disk-usage # display disk space occupied by rvm
notes # display notes with operating system specifics
version # display rvm version (equal to `rvm -v`)

additional global options
--debug # toggle debug mode on for very verbose output
--trace # toggle trace mode on to see EVERYTHING rvm is doing
--nice # process niceness (increase the value on slow computers, default 0)

For additional documentation please visit


$ rails -h
rails new APP_PATH [options]

[--skip-namespace], [--no-skip-namespace] # Skip namespace (affects only isolated engines)
[--skip-collision-check], [--no-skip-collision-check] # Skip collision check
-r, [--ruby=PATH] # Path to the Ruby binary of your choice
# Default: /usr/local/rvm/rubies/ruby-2.5.8/bin/ruby
-m, [--template=TEMPLATE] # Path to some application template (can be a filesystem path or URL)
-d, [--database=DATABASE] # Preconfigure for selected database (options: mysql/postgresql/sqlite3/oracle/sqlserver/jdbcmysql/jdbcsqlite3/jdbcpostgresql/jdbc)
# Default: sqlite3
[--skip-gemfile], [--no-skip-gemfile] # Don't create a Gemfile
-G, [--skip-git], [--no-skip-git] # Skip .gitignore file
[--skip-keeps], [--no-skip-keeps] # Skip source control .keep files
-M, [--skip-action-mailer], [--no-skip-action-mailer] # Skip Action Mailer files
[--skip-action-mailbox], [--no-skip-action-mailbox] # Skip Action Mailbox gem
[--skip-action-text], [--no-skip-action-text] # Skip Action Text gem
-O, [--skip-active-record], [--no-skip-active-record] # Skip Active Record files
[--skip-active-job], [--no-skip-active-job] # Skip Active Job
[--skip-active-storage], [--no-skip-active-storage] # Skip Active Storage files
-P, [--skip-puma], [--no-skip-puma] # Skip Puma related files
-C, [--skip-action-cable], [--no-skip-action-cable] # Skip Action Cable files
-S, [--skip-sprockets], [--no-skip-sprockets] # Skip Sprockets files
[--skip-spring], [--no-skip-spring] # Don't install Spring application preloader
[--skip-listen], [--no-skip-listen] # Don't generate configuration that depends on the listen gem
-J, [--skip-javascript], [--no-skip-javascript] # Skip JavaScript files
[--skip-turbolinks], [--no-skip-turbolinks] # Skip turbolinks gem
[--skip-jbuilder], [--no-skip-jbuilder] # Skip jbuilder gem
-T, [--skip-test], [--no-skip-test] # Skip test files
[--skip-system-test], [--no-skip-system-test] # Skip system test files
[--skip-bootsnap], [--no-skip-bootsnap] # Skip bootsnap gem
[--dev], [--no-dev] # Set up the application with Gemfile pointing to your Rails checkout
[--edge], [--no-edge] # Set up the application with Gemfile pointing to Rails repository
[--master], [--no-master] # Set up the application with Gemfile pointing to Rails repository main branch
[--rc=RC] # Path to file containing extra configuration options for rails command
[--no-rc], [--no-no-rc] # Skip loading of extra configuration options from .railsrc file
[--api], [--no-api] # Preconfigure smaller stack for API only apps
[--minimal], [--no-minimal] # Preconfigure a minimal rails app
-B, [--skip-bundle], [--no-skip-bundle] # Don't run bundle install
--webpacker, [--webpack=WEBPACK] # Preconfigure Webpack with a particular framework (options: react, vue, angular, elm, stimulus)
[--skip-webpack-install], [--no-skip-webpack-install] # Don't run Webpack install

Runtime options:
-f, [--force] # Overwrite files that already exist
-p, [--pretend], [--no-pretend] # Run but do not make any changes
-q, [--quiet], [--no-quiet] # Suppress status output
-s, [--skip], [--no-skip] # Skip files that already exist

Rails options:
-h, [--help], [--no-help] # Show this help message and quit
-v, [--version], [--no-version] # Show Rails version number and quit

The 'rails new' command creates a new Rails application with a default
directory structure and configuration at the path you specify.

You can specify extra command-line arguments to be used every time
'rails new' runs in the .railsrc configuration file in your home directory,
or in $XDG_CONFIG_HOME/rails/railsrc if XDG_CONFIG_HOME is set.

Note that the arguments specified in the .railsrc file don't affect the
defaults values shown above in this help message.

rails new ~/Code/Ruby/weblog

This generates a skeletal Rails installation in ~/Code/Ruby/weblog.


$ ruby -h
Usage: ruby [switches] [--] [programfile] [arguments]
-0[octal] specify record separator (\0, if no argument)
-a autosplit mode with -n or -p (splits $_ into $F)
-c check syntax only
-Cdirectory cd to directory before executing your script
-d set debugging flags (set $DEBUG to true)
-e 'command' one line of script. Several -e's allowed. Omit [programfile]
-Eex[:in] specify the default external and internal character encodings
-Fpattern split() pattern for autosplit (-a)
-i[extension] edit ARGV files in place (make backup if extension supplied)
-Idirectory specify $LOAD_PATH directory (may be used more than once)
-l enable line ending processing
-n assume 'while gets(); ... end' loop around your script
-p assume loop like -n but print line also like sed
-rlibrary require the library before executing your script
-s enable some switch parsing for switches after script name
-S look for the script using PATH environment variable
-T[level=1] turn on tainting checks
-v print version number, then turn on verbose mode
-w turn warnings on for your script
-W[level=2] set warning level; 0=silence, 1=medium, 2=verbose
-x[directory] strip off text before #!ruby line and perhaps cd to directory
-h show this message, --help for more info