I name this script railstrunk on my machine. So, usage would be:

railstrunk app_name

That creates a rails application under app_name.

If app_name is a subversion working copy, rails is set as an external and generated files are committed, and some ignore properties are set.

Here's how I'd go about creating a versioned rails app:

mkdir -p happy_app happy_app/trunk happy_app/tags happy_app/branches 
svn import happy_app http://myserver/myrepos/happy_app -m "Layout for happy_app"
rm -rf happy_app
svn co http://myserver/myrepos/happy_app/trunk happy_app
railstrunk happy_app

$rails_dir is set at the beginning of script, and it should be a path to a working copy of rails trunk on your machine. It's merely used to speed things up, it's not necessary.

Notice I remove the silly public/index.html from the generated app.

And now the code:

#!/bin/bash

rails_dir=~/code/ruby/rails

if [ $# != 1 ]; then
  echo "Usage: $0 app_name"
  echo
  echo "Creates a rails application under app_name."
  echo
  echo "If app_name is a subversion working copy, rails is set as an external"
  echo "and generated files are committed."
  echo
  echo "If $rails_dir exists, things are sped up by either symlinking it"
  echo "(for non-versioned apps) or copying it to the vendor dir."
  echo
  echo "$rails_dir should be a rails trunk working copy."
  exit
fi

dir=$1
mkdir -p $dir
cd $dir

if [ -n "`ls`" ]; then
  echo "Can't create app: $dir is not empty." >&2
  exit 1
fi

if [ -d $rails_dir ]; then
  if [ "`svn info $rails_dir 2>/dev/null | grep URL:`" != "URL: http://dev.rubyonrails.org/svn/rails/trunk" ]; then
    echo "$rails_dir is not a rails trunk working copy. Not going to use it." >&2
  elif [ -n "`svn st $rails_dir`" ]; then
    echo "$rails_dir is modified. Not going to use it." >&2
  else
    use_rails_dir=1
  fi
fi

if [ -z "`svn info 2>/dev/null`" ]; then
  mkdir vendor
  if [ -n "$use_rails_dir" ]; then
    ln -s $rails_dir vendor/rails
    cd vendor/rails
    svn up
    cd ../..
  else
    svn co http://dev.rubyonrails.org/svn/rails/trunk vendor/rails
  fi
  ruby vendor/rails/railties/bin/rails .
  rm public/index.html
else
  svn mkdir vendor
  svn ps svn:externals 'rails http://dev.rubyonrails.org/svn/rails/trunk' vendor
  svn ci -m 'set rails external to rails trunk'
  [ -n "$use_rails_dir" ] && cp -r $rails_dir vendor/rails
  svn up
  ruby vendor/rails/railties/bin/rails .
  rm public/index.html
  rm log/*
  mv config/database.yml config/database.yml.sample
  svn add . --force
  svn ps svn:ignore '*' tmp/cache tmp/pids tmp/sessions tmp/sockets
  svn ps svn:ignore 'database.yml' config
  svn ps svn:ignore '*.log' log
  svn ci -m "- created rails app
- moved database.yml to database.yml.sample
- deleted public/index.html
- ignored logs and tmp"
  cp config/database.yml.sample config/database.yml
fi

If you have an app in subversion with many externals, it may take a bit too long to update it, as updates happen one after another.

This bit of script updates the app and each external in parallel, making it oh so much faster.

#!/usr/local/bin/ruby

puts(
  ( `svn pl -R`.scan(/\S.*'(.*)':\n((?:  .*\n)+)/)\
    .inject({}) { |h, (d, p)| h[d] = p.strip.split(/\s+/); h }\
    .select { |d, ps| ps.include? 'svn:externals' }\
    .map { |xd, ps| [xd, `svn pg svn:externals #{xd}`] }\
    .map { |xd, exts| exts.strip.split(/\s*\n/).map { |l| xd + '/' + l.split(/\s+/).first } }\
    .inject { |a, b| a + b }\
    .map { |d| "cd #{d} && svn up 2>&1" } \
    << 'svn up . --ignore-externals 2>&1'
  )\
  .map { |cmd| [cmd, Thread.new { `#{cmd}` }] }\
  .map { |cmd, thread| "#{cmd}\n#{thread.value}" }.join("\n")
)

(note: if you add an external or change an external property in another way, you'll need to run the standard svn up once)

perl -pi -e 's|^#!/.*|#!/usr/bin/env ruby|;' script/* script/*/* public/dispatch.*

This will pass all matched filenames to textmate, generating a project with all files flatly in the drawer (no dirs)

egrep -lr pattern * | grep -v .svn | xargs mate

Wanna know what gems you have installed without looking at all the descriptions?

gem list | egrep -v "^( |$)"

Here's a (trimmed) sample output:

$ gem list | egrep -v "^ |^$"
*** LOCAL GEMS ***
actionmailer (1.2.1, 1.2.0, 1.1.5)
actionpack (1.12.1, 1.12.0, 1.11.2)
actionwebservice (1.1.2, 1.1.1, 1.1.0, 1.0.0)
activerecord (1.14.2, 1.14.1, 1.14.0, 1.13.2)
activesupport (1.3.1, 1.3.0, 1.2.5)
BlueCloth (1.0.0)
capistrano (1.1.0)
diff-lcs (1.1.2)