pyenv/libexec/rbenv-help

#!/usr/bin/env bash
set -e

print_set_version() {
  echo "<version> should be a string matching a Ruby version known by rbenv."

  local versions="$(rbenv-versions --bare)"
  if [ -z "$versions" ]; then
    echo "There are currently no Ruby versions installed for rbenv."
  else
    echo "The currently installed Ruby versions are:"
    echo "$versions" | sed 's/^/  /'
  fi

  echo
  echo "The special version string 'system' will use your default system Ruby."
}

case "$1" in
"") echo "usage: rbenv <command> [<args>]

Some useful rbenv commands are:
   commands      List all commands
   rehash        Rehash rbenv shims (run this after installing binaries)
   set-default   Set the default Ruby version
   set-local     Set a local directory-specific Ruby version
   version       Show the current Ruby version
   versions      List all Ruby versions known by rbenv

See 'rbenv help <command>' for more information on a specific command.
For more information, see: https://github.com/sstephenson/rbenv#readme"
;;
set-default) echo "usage: rbenv set-default <version>

Sets the default Ruby version. You can override the default at any time
by setting a directory-specific version with \`rbenv set-local' or by
setting the RBENV_VERSION environment variable.

$(print_set_version)"
;;
set-local) echo "usage: rbenv set-local <version>

Sets the local directory-specific Ruby version by writing the version
name to a file named '.rbenv-version'.

When you run a Ruby command, rbenv will look for an '.rbenv-version'
file in the current directory and each parent directory. If no such
file is found in the tree, rbenv will use the default Ruby version
specified with \`rbenv set-default', or the version specified in the
RBENV_VERSION environment variable.

$(print_set_version)"
;;
*) echo "No command arguments needed or invalid/undocumented command."
esac