chage-ruby script

gistfile1.sh

#!/bin/sh

BIN_DIR=/usr/bin
RUBY18_BIN_DIR=/usr/bin
RUBY19_BIN_DIR=/opt/ruby-1.9/bin
GEMS_HOME=/var/lib/gems

if([ -z "$1" ] || ([ "$1" != "1.8" ] && [ "$1" != "1.9" ]))
then
  echo "Usage: change_ruby VERSION (1.8 or 1.9)"
  exit 1
fi

remove_symlinks() {
  for file in erb gem irb rake rdoc ri ruby testrb
  do
    rm -f $BIN_DIR/$file
  done
  rm -f $GEMS_HOME/bin
}

create_symlinks() {
  ruby_version=$1

  case "$ruby_version" in
    "1.8" ) ruby_bin_dir=$RUBY18_BIN_DIR;;
    "1.9" ) ruby_bin_dir=$RUBY19_BIN_DIR;;
  esac

  for file in erb gem irb rake rdoc ri ruby testrb
  do
    ln -s $ruby_bin_dir/$file$ruby_version $BIN_DIR/$file
  done

  ln -s $GEMS_HOME/$ruby_version/bin $GEMS_HOME/bin
}

remove_symlinks
create_symlinks $1

exit