ERB(1) Ruby Programmer's Reference Guide ERB(1)
NAME
erb — Ruby Templating
SYNOPSIS
erb [--version] [-UPdnvx] [-E ext[:int]] [-S level] [-T mode]
[-r library] [--] [file ...]
DESCRIPTION
erb is a command line front-end for ERB library, which is an implementa-
tion of eRuby.
ERB provides an easy to use but powerful templating system for Ruby.
Using ERB, actual Ruby code can be added to any plain text document for
the purposes of generating document information details and/or flow con-
trol.
erb is a part of Ruby.
OPTIONS
--version Prints the version of erb.
-E external[:internal]
--encoding external[:internal]
Specifies the default value(s) for external encodings and
internal encoding. Values should be separated with colon
(:).
You can omit the one for internal encodings, then the
value (Encoding.default_internal) will be nil.
-P Disables ruby code evaluation for lines beginning with %.
-S level Specifies the safe level in which eRuby script will run.
-T mode Specifies trim mode (default 0). mode can be one of
0 EOL remains after the embedded ruby script
is evaluated.
1 EOL is removed if the line ends with %>.
2 EOL is removed if the line starts with <%
and ends with %>.
- EOL is removed if the line ends with -%>.
And leading whitespaces are removed if the
erb directive starts with <%-.
-r Load a library
-U can be one of Sets the default value for internal encod-
ings (Encoding.default_internal) to UTF-8.
-d
--debug Turns on debug mode. $DEBUG will be set to true.
-h
--help Prints a summary of the options.
-n Used with -x. Prepends the line number to each line in
the output.
-v Enables verbose mode. $VERBOSE will be set to true.
-x Converts the eRuby script into Ruby script and prints it
without line numbers.
EXAMPLES
Here is an eRuby script
<?xml version="1.0" ?>
<% require 'prime' -%>
<erb-example>
<calc><%= 1+1 %></calc>
<var><%= __FILE__ %></var>
<library><%= Prime.each(10).to_a.join(", ") %></library>
</erb-example>
Command
% erb -T - example.erb
prints
<?xml version="1.0" ?>
<erb-example>
<calc>2</calc>
<var>example.erb</var>
<library>2, 3, 5, 7</library>
</erb-example>
SEE ALSO
ruby(1).
And see ri(1) documentation for ERB class.
REPORTING BUGS
• Security vulnerabilities should be reported via an email to
security@ruby-lang.org. Reported problems will be published after
being fixed.
• Other bugs and feature requests can be reported via the Ruby Issue
Tracking System (https://bugs.ruby-lang.org/). Do not report secu-
rity vulnerabilities via this system because it publishes the vul-
nerabilities immediately.
AUTHORS
Written by Masatoshi SEKI.
UNIX December 16, 2018 ERB(1)
Generated by dwww version 1.16 on Tue Dec 16 06:28:46 CET 2025.