For erb text highlighting in gedit. put it here: /usr/share/gtksourceview-2.0/language-specs/

erb.lang

<?xml version="1.0" encoding="UTF-8"?>
<!--
 This is a smashup by Justin Richter of html.lang and ruby.lang
 html.lang 
   Authors: Marco Barisione, Emanuele Aina
   Copyright (C) 2005-2007 Marco Barisione <barisione@gmail.com>
   Copyright (C) 2005-2007 Emanuele Aina
 ruby.lang 
   Author: Archit Baweja <bighead@users.sourceforge.net>
   Copyright (C) 2004 Archit Baweja <bighead@users.sourceforge.net>
   Copyright (C) 2005 Michael Witrant <mike@lepton.fr>
   Copyright (C) 2006 Gabriel Bauman <gbauman@gmail.com>

 This library is free software; you can redistribute it and/or modify
 it under the terms of the GNU General Public License as published by
 the Free Software Foundation; either version 2 of the License, or
 (at your option) any later version.

 This program is distributed in the hope that it will be useful,
 but WITHOUT ANY WARRANTY; without even the implied warranty of
 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 GNU General Public License for more details.

 You should have received a copy of the GNU General Public License
 along with this program; if not, write to the Free Software
 Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA

-->
<language id="erb" _name="Ruby(ERB/RHTML)" version="2.0" _section="Scripts">
  <metadata>
    <property name="mimetypes">application/x-ruby;text/x-ruby</property>
    <property name="globs">*.erb;*.rhtml</property>
    <property name="line-comment-start">#</property>
  </metadata>

  <styles>
    <style id="escape"               _name="Escaped Character"      map-to="def:special-char"/>
    <style id="comment"              _name="Comment"               map-to="def:comment"/>
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    <style id="module-handler"       _name="Module handler"        map-to="def:preprocessor"/>
    <style id="keyword"              _name="Keyword"               map-to="def:keyword"/>
    <style id="nil-value"            _name="Nil Constant"          map-to="def:special-constant"/>
    <style id="boolean"              _name="Boolean value"         map-to="def:boolean"/>
    <style id="floating-point"       _name="Floating point number" map-to="def:floating-point"/>
    <style id="decimal"              _name="Decimal number"        map-to="def:decimal"/>
    <style id="base-n-integer"       _name="Base-N number"         map-to="def:base-n-integer"/>
    <style id="numeric-literal"      _name="Numeric literal"       map-to="def:base-n-integer"/>
    <style id="string"               _name="String"                map-to="def:string"/>
    <style id="builtin"              _name="Builtin"               map-to="def:type"/>
    <style id="constant"             _name="Constant"              map-to="def:type"/>
    <style id="symbol"               _name="Symbol"                map-to="def:string"/>
    <style id="special-variable"     _name="Special Variable"      map-to="def:identifier"/>
    <style id="predefined-variable"  _name="Predefined Variable"   map-to="def:identifier"/>
    <style id="variable"             _name="Variable"              map-to="def:identifier"/>
    <style id="here-doc"             _name="Heredoc"               map-to="def:string" />
    <style id="here-doc-bound"       _name="Heredoc Bound"         map-to="def:string"/>
    <style id="regex"                _name="Regular Expression"    map-to="def:identifier"/>
    <style id="tag"                  _name="Tag"                   map-to="xml:element-name"/>
    <style id="attrib-name"          _name="Attribute Name"        map-to="xml:attribute-name"/>
    <style id="attrib-value"         _name="Attribute Value"       map-to="xml:attribute-value"/>
    <style id="dtd"                  _name="DTD"                   map-to="xml:doctype"/>
    <style id="error"                _name="Error"                 map-to="xml:error"/>
  </styles>

  <definitions>

    <context id="escape" style-ref="escape">
      <match>\\((0-7){3}|(x[a-fA-F0-9]{2})|(c\S)|([CM]-\S)|(M-C-\S)|.)</match>
    </context>

    <context id="multiline-comment" style-ref="comment">
      <start>^=begin</start>
      <end>^=end</end>
      <include>
        <context ref="escape"/>
        <context ref="def:in-comment"/>
      </include>
    </context>

    <context id="attribute-definitions" style-ref="attribute-definition">
      <keyword>attr</keyword>
      <keyword>attr_writer</keyword>
      <keyword>attr_reader</keyword>
      <keyword>attr_accessor</keyword>
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    <context id="definitions" style-ref="keyword">
      <!-- do not highlight the .class method -->
      <prefix>(?&lt;![\w\.])</prefix>
      <keyword>alias</keyword>
      <keyword>class</keyword>
      <keyword>module</keyword>
      <keyword>def</keyword>
      <keyword>undef</keyword>
    </context>

    <context id="module-handlers" style-ref="module-handler">
      <keyword>require</keyword>
      <keyword>include</keyword>
      <keyword>load</keyword>
    </context>

    <context id="keywords" style-ref="keyword">
      <keyword>BEGIN</keyword>
      <keyword>END</keyword>
      <keyword>and</keyword>
      <keyword>begin</keyword>
      <keyword>break</keyword>
      <keyword>case</keyword>
      <keyword>catch</keyword>
      <keyword>defined?</keyword>
      <keyword>do</keyword>
      <keyword>else</keyword>
      <keyword>elsif</keyword>
      <keyword>end</keyword>
      <keyword>ensure</keyword>
      <keyword>for</keyword>
      <keyword>if</keyword>
      <keyword>in</keyword>
      <keyword>next</keyword>
      <keyword>not</keyword>
      <keyword>or</keyword>
      <keyword>private</keyword>
      <keyword>protected</keyword>
      <keyword>public</keyword>
      <keyword>redo</keyword>
      <keyword>rescue</keyword>
      <keyword>retry</keyword>
      <keyword>return</keyword>
      <keyword>then</keyword>
      <keyword>throw</keyword>
      <keyword>unless</keyword>
      <keyword>until</keyword>
      <keyword>when</keyword>
      <keyword>while</keyword>
      <keyword>yield</keyword>
    </context>

    <context id="builtins" style-ref="builtin">
      <keyword>ARGF</keyword>
      <keyword>ARGV</keyword>
      <keyword>Abbrev</keyword>
      <keyword>ArgumentError</keyword>
      <keyword>Array</keyword>
      <keyword>Base64</keyword>
      <keyword>Benchmark::Tms</keyword>
      <keyword>Benchmark</keyword>
      <keyword>Bignum</keyword>
      <keyword>Binding</keyword>
      <keyword>CGI::Cookie</keyword>
      <keyword>CGI::HtmlExtension</keyword>
      <keyword>CGI::QueryExtension</keyword>
      <keyword>CGI::Session::FileStore</keyword>
      <keyword>CGI::Session::MemoryStore</keyword>
      <keyword>CGI::Session</keyword>
      <keyword>CGI</keyword>
      <keyword>Class</keyword>
      <keyword>Comparable</keyword>
      <keyword>Complex</keyword>
      <keyword>ConditionVariable</keyword>
      <keyword>Continuation</keyword>
      <keyword>DATA</keyword>
      <keyword>Data</keyword>
      <keyword>Date</keyword>
      <keyword>DateTime</keyword>
      <keyword>Delegator</keyword>
      <keyword>Dir</keyword>
      <keyword>ENV</keyword>
      <keyword>EOFError</keyword>
      <keyword>ERB::Util</keyword>
      <keyword>ERB</keyword>
      <keyword>Enumerable::Enumerator</keyword>
      <keyword>Enumerable</keyword>
      <keyword>Errno</keyword>
      <keyword>Exception</keyword>
      <keyword>FalseClass</keyword>
      <keyword>File::Constants</keyword>
      <keyword>File::Stat</keyword>
      <keyword>File</keyword>
      <keyword>FileTest</keyword>
      <keyword>FileUtils::DryRun</keyword>
      <keyword>FileUtils::NoWrite</keyword>
      <keyword>FileUtils::StreamUtils</keyword>
      <keyword>FileUtils::Verbose</keyword>
      <keyword>FileUtils</keyword>
      <keyword>Find</keyword>
      <keyword>Fixnum</keyword>
      <keyword>Float</keyword>
      <keyword>FloatDomainError</keyword>
      <keyword>Forwardable</keyword>
      <keyword>GC</keyword>
      <keyword>Generator</keyword>
      <keyword>Hash</keyword>
      <keyword>IO</keyword>
      <keyword>IOError</keyword>
      <keyword>Iconv::BrokenLibrary</keyword>
      <keyword>Iconv::Failure</keyword>
      <keyword>Iconv::IllegalSequence</keyword>
      <keyword>Iconv::InvalidCharacter</keyword>
      <keyword>Iconv::InvalidEncoding</keyword>
      <keyword>Iconv::OutOfRange</keyword>
      <keyword>Iconv</keyword>
      <keyword>IndexError</keyword>
      <keyword>Integer</keyword>
      <keyword>Interrupt</keyword>
      <keyword>Kernel</keyword>
      <keyword>LoadError</keyword>
      <keyword>LocalJumpError</keyword>
      <keyword>Logger::Application</keyword>
      <keyword>Logger::Error</keyword>
      <keyword>Logger::Formatter</keyword>
      <keyword>Logger::LogDevice::LogDeviceMutex</keyword>
      <keyword>Logger::LogDevice</keyword>
      <keyword>Logger::Severity</keyword>
      <keyword>Logger::ShiftingError</keyword>
      <keyword>Logger</keyword>
      <keyword>Marshal</keyword>
      <keyword>MatchData</keyword>
      <keyword>Math</keyword>
      <keyword>Matrix</keyword>
      <keyword>Method</keyword>
      <keyword>Module</keyword>
      <keyword>Mutex</keyword>
      <keyword>NameError::message</keyword>
      <keyword>NameError</keyword>
      <keyword>NilClass</keyword>
      <keyword>NoMemoryError</keyword>
      <keyword>NoMethodError</keyword>
      <keyword>NotImplementedError</keyword>
      <keyword>Numeric</keyword>
      <keyword>Object</keyword>
      <keyword>ObjectSpace</keyword>
      <keyword>Observable</keyword>
      <keyword>PStore::Error</keyword>
      <keyword>PStore</keyword>
      <keyword>Pathname</keyword>
      <keyword>Precision</keyword>
      <keyword>Proc</keyword>
      <keyword>Process::GID</keyword>
      <keyword>Process::Status</keyword>
      <keyword>Process::Sys</keyword>
      <keyword>Process::UID</keyword>
      <keyword>Process</keyword>
      <keyword>Queue</keyword>
      <keyword>RUBY_PLATFORM</keyword>
      <keyword>RUBY_RELEASE_DATE</keyword>
      <keyword>RUBY_VERSION</keyword>
      <keyword>Range</keyword>
      <keyword>RangeError</keyword>
      <keyword>Rational</keyword>
      <keyword>Regexp</keyword>
      <keyword>RegexpError</keyword>
      <keyword>RuntimeError</keyword>
      <keyword>STDERR</keyword>
      <keyword>STDIN</keyword>
      <keyword>STDOUT</keyword>
      <keyword>ScriptError</keyword>
      <keyword>SecurityError</keyword>
      <keyword>Set</keyword>
      <keyword>Shellwords</keyword>
      <keyword>Signal</keyword>
      <keyword>SignalException</keyword>
      <keyword>SimpleDelegator</keyword>