I’ll explain how to install multiple gems with the specific version.
Install gem normally
First of all, how to install a gem normally.
Just run gem install gem_name.
In the following example, install rubocop gem.
$ gem i rubocop
Fetching regexp_parser-2.0.3.gem
Fetching ast-2.4.2.gem
Fetching unicode-display_width-2.0.0.gem
Fetching ruby-progressbar-1.11.0.gem
Fetching parser-3.0.0.0.gem
Fetching rubocop-ast-1.4.1.gem
Fetching rainbow-3.0.0.gem
Fetching rubocop-1.9.1.gem
Fetching parallel-1.20.1.gem
Successfully installed unicode-display_width-2.0.0
Successfully installed ruby-progressbar-1.11.0
Successfully installed ast-2.4.2
Successfully installed parser-3.0.0.0
Successfully installed rubocop-ast-1.4.1
Successfully installed regexp_parser-2.0.3
Successfully installed rainbow-3.0.0
Successfully installed parallel-1.20.1
Successfully installed rubocop-1.9.1
9 gems installed
The latest version of the gem will be installed. In this example, rubocop 1.9 was installed.
Install gem with version
Let’s specify the version of gem with -v option.
$ gem i rubocop -v 1.0.0
Or, you can use gem_name:version
$ gem i rubocop:1.0
Fetching parser-3.0.0.0.gem
Fetching rainbow-3.0.0.gem
Fetching ast-2.4.2.gem
Fetching ruby-progressbar-1.11.0.gem
Fetching rubocop-1.0.0.gem
Fetching unicode-display_width-1.7.0.gem
Fetching regexp_parser-2.0.3.gem
Fetching rubocop-ast-1.4.1.gem
Fetching parallel-1.20.1.gem
Successfully installed unicode-display_width-1.7.0
Successfully installed ruby-progressbar-1.11.0
Successfully installed ast-2.4.2
Successfully installed parser-3.0.0.0
Successfully installed rubocop-ast-1.4.1
Successfully installed regexp_parser-2.0.3
Successfully installed rainbow-3.0.0
Successfully installed parallel-1.20.1
Successfully installed rubocop-1.0.0
9 gems installed
Install multiple gems with version
How about installing multiple gems with version?
Let’s install rubocop v1.0.0 and rubocop-ast v1.0.0.
$ gem i rubocop-ast:1.0 rubocop:1.0
Fetching parser-3.0.0.0.gem
Fetching ast-2.4.2.gem
Fetching rubocop-ast-1.0.0.gem
Successfully installed ast-2.4.2
Successfully installed parser-3.0.0.0
Successfully installed rubocop-ast-1.0.0
Fetching ruby-progressbar-1.11.0.gem
Fetching rubocop-1.0.0.gem
Fetching regexp_parser-2.0.3.gem
Fetching rainbow-3.0.0.gem
Fetching parallel-1.20.1.gem
Fetching unicode-display_width-1.7.0.gem
Successfully installed unicode-display_width-1.7.0
Successfully installed ruby-progressbar-1.11.0
Successfully installed regexp_parser-2.0.3
Successfully installed rainbow-3.0.0
Successfully installed parallel-1.20.1
Successfully installed rubocop-1.0.0
9 gems installed
Check the versions.
$ gem list | grep rubocop
rubocop (1.0.0)
rubocop-ast (1.0.0)
Install child dependency first
Heads up: install child dependency first, otherwise other version will also be installed.
$ gem i rubocop:1.0 rubocop-ast:1.0
Fetching rainbow-3.0.0.gem
Fetching regexp_parser-2.0.3.gem
Fetching parser-3.0.0.0.gem
Fetching ruby-progressbar-1.11.0.gem
Fetching parallel-1.20.1.gem
Fetching rubocop-1.0.0.gem
Fetching ast-2.4.2.gem
Fetching rubocop-ast-1.4.1.gem
Fetching unicode-display_width-1.7.0.gem
Successfully installed unicode-display_width-1.7.0
Successfully installed ruby-progressbar-1.11.0
Successfully installed ast-2.4.2
Successfully installed parser-3.0.0.0
Successfully installed rubocop-ast-1.4.1
Successfully installed regexp_parser-2.0.3
Successfully installed rainbow-3.0.0
Successfully installed parallel-1.20.1
Successfully installed rubocop-1.0.0
Fetching rubocop-ast-1.0.0.gem
Successfully installed rubocop-ast-1.0.0
10 gems installed
In this example, rubocop-ast v1.4 has been installed as well as v1.0.
$ gem list | grep rubocop
rubocop (1.0.0)
rubocop-ast (1.4.1, 1.0.0)