How To Uninstall Old Versions Of Ruby Gems

Overview

Chances are that if you have been using Ruby for a while, your system will be full of gems and more specifically, outdated gems.

Every time you perform an update with $ gem update the default behaviour is to install a new gem version maintaining the older one.

The update command does not remove the previous version.

Removing old unused gems

To remove older gems we use the clean command:

The cleanup command removes old versions of gems from GEM_HOME that are not required to meet a dependency. If a gem is installed elsewhere in GEM_PATH the cleanup command won't delete it.

If no gems are named all gems in GEM_HOME are cleaned.

We can choose to specify a gem to remove its older versions or remove every old gem:

$ gem cleanup
Cleaning up installed gems...
Attempting to uninstall test-unit-3.1.7
Unable to uninstall test-unit-3.1.7:
        Gem::InstallError: test-unit is not installed in GEM_HOME, try:
        gem uninstall -i /usr/share/rubygems-integration/all test-unit
Attempting to uninstall public_suffix-2.0.4
Successfully uninstalled public_suffix-2.0.4
Attempting to uninstall power_assert-0.2.7
Unable to uninstall power_assert-0.2.7:
        Gem::InstallError: power_assert is not installed in GEM_HOME, try:
        gem uninstall -i /usr/share/rubygems-integration/all power_assert
Attempting to uninstall nokogiri-1.6.8.1
Successfully uninstalled nokogiri-1.6.8.1
Attempting to uninstall minitest-5.9.0
Unable to uninstall minitest-5.9.0:
        Gem::InstallError: minitest is not installed in GEM_HOME, try:
        gem uninstall -i /usr/share/rubygems-integration/all minitest
Attempting to uninstall rb-inotify-0.9.7
Successfully uninstalled rb-inotify-0.9.7
Attempting to uninstall kramdown-1.12.0
Successfully uninstalled kramdown-1.12.0
Attempting to uninstall jekyll-seo-tag-2.0.0
Successfully uninstalled jekyll-seo-tag-2.0.0
Attempting to uninstall jekyll-3.3.0
Successfully uninstalled jekyll-3.3.0
Attempting to uninstall jekyll-sass-converter-1.4.0
Successfully uninstalled jekyll-sass-converter-1.4.0
Attempting to uninstall sass-3.4.22
Successfully uninstalled sass-3.4.22
Attempting to uninstall kramdown-1.13.1
Successfully uninstalled kramdown-1.13.1
Attempting to uninstall html-proofer-3.3.1
Successfully uninstalled html-proofer-3.3.1
Attempting to uninstall parallel-1.9.0
Successfully uninstalled parallel-1.9.0
Attempting to uninstall nokogiri-1.7.0
Successfully uninstalled nokogiri-1.7.0

Address errors

The above command uninstall most of the gems but it can’t deal with some of them showing messages like:

Attempting to uninstall minitest-5.9.0
Unable to uninstall minitest-5.9.0:
		Gem::InstallError: minitest is not installed in GEM_HOME, try:
		gem uninstall -i /usr/share/rubygems-integration/all minitest

To uninstall them we run the command again, executing the suggested command gem uninstall ...:

sudo gem cleanup | grep -Z "gem uninstall"| while read -r line ; do 
    echo "Uninstalling $line"; 
	tee sudo "$line"; 
done

References

• Removing old versions of gems
• How to process each line received as a result of grep command