How to uninstall all gems installed using `bundle install`

Question

How can I remove all the gems installed using bundle install in a particular RoR project. I don\'t want to uninstall gems that are used by other projects.

Answer 1

Another way from https://makandracards.com/jan0sch/9537-uninstall-all-ruby-gems-from-your-system (similar to rainkinz's answer and Ralph's comment). Here are some variations:

# if you're the root user:
gem list | cut -d" " -f1 | xargs -I % gem uninstall -aIx %

# if you're a non-root user:
gem list | cut -d" " -f1 | xargs -I % sudo gem uninstall -aIx %

# docker compose (if your service is named "web" running the root user):
docker-compose run web bash -c 'gem list | cut -d" " -f1 | xargs -I % gem uninstall -aIx %'

####

gem install bundler
# or if using docker compose:
docker-compose run web gem install bundler

# optionally reinstall gems:
bundle install
# or if using docker compose:
docker-compose run web bundle install

Breaking this down:

• gem list lists all gems
• cut -d" " -f1 takes the first column
• xargs -I % gem uninstall -aIx % calls gem uninstall -aIx with each output line as an argument

Note that I specified the argument with -I as % and passed it directly for security:

xargs -I % gem uninstall -aIx %

instead of:

xargs gem uninstall -aIx

That's because xargs has a security issue where options like -n can be passed to its command and cause unexpected results. This can be demonstrated with the following example:

# correctly prints "-n hello" (with trailing newline):
echo '-n Hello' | xargs -I % echo % | xargs -I % echo %

# incorrectly prints "hello" (without trailing newline):
echo '-n Hello' | xargs echo