check: Flags: –dry-run, –help, -h. Valued: –gemfile, –path
info: Flags: –help, –path, -h
install: Flags: –help, -h
list: Flags: –help, –name-only, –paths, -h
show: Flags: –help, –paths, -h
Allowed standalone flags: –help, –version, -V, -h

`gem`

https://guides.rubygems.org/command-reference/

contents: Flags: –all, –help, –local, –prerelease, –remote, –versions, -a, -h, -i, -l, -r. Valued: –version, -v
dependency: Flags: –all, –help, –local, –prerelease, –remote, –versions, -a, -h, -i, -l, -r. Valued: –version, -v
environment: Flags: –all, –help, –local, –prerelease, –remote, –versions, -a, -h, -i, -l, -r. Valued: –version, -v
help: Flags: –all, –help, –local, –prerelease, –remote, –versions, -a, -h, -i, -l, -r. Valued: –version, -v
info: Flags: –help, –installed, –prerelease, -h, -i. Valued: –version, -v
list: Flags: –all, –help, –installed, –local, –no-details, –no-versions, –prerelease, –remote, –versions, -a, -d, -h, -i, -l, -r
outdated: Flags: –all, –help, –local, –prerelease, –remote, –versions, -a, -h, -i, -l, -r. Valued: –version, -v
pristine: Flags: –all, –help, –local, –prerelease, –remote, –versions, -a, -h, -i, -l, -r. Valued: –version, -v
search: Flags: –all, –details, –exact, –help, –local, –prerelease, –remote, –versions, -a, -d, -e, -h, -i, -l, -r
sources: Flags: –all, –help, –local, –prerelease, –remote, –versions, -a, -h, -i, -l, -r. Valued: –version, -v
specification: Flags: –all, –help, –local, –prerelease, –remote, –versions, -a, -h, -i, -l, -r. Valued: –version, -v
stale: Flags: –all, –help, –local, –prerelease, –remote, –versions, -a, -h, -i, -l, -r. Valued: –version, -v
which: Flags: –all, –help, –local, –prerelease, –remote, –versions, -a, -h, -i, -l, -r. Valued: –version, -v
Allowed standalone flags: –help, –version, -V, -h