EPERL(1) Ralf S. Engelschall EPERL(1)NAME
ePerl - Embedded Perl 5 Language
VERSION
@V@
SYNOPSISeperl [-d name=value] [-D name=value] [-B begin_delimiter] [-E
end_delimiter] [-i] [-m mode] [-o outputfile] [-k] [-I directory] [-P]
[-C] [-L] [-x] [-T] [-w] [-c] [inputfile]
eperl [-r] [-l] [-v] [-V]
DESCRIPTION
Abstract
ePerl interprets an ASCII file bristled with Perl 5 program statements
by evaluating the Perl 5 code while passing through the plain ASCII
data. It can operate in various ways: As a stand-alone Unix filter or
integrated Perl 5 module for general file generation tasks and as a
powerful Webserver scripting language for dynamic HTML page
programming.
Introduction
The eperl program is the Embedded Perl 5 Language interpreter. This
really is a full-featured Perl 5 interpreter, but with a different
calling environment and source file layout than the default Perl
interpreter (usually the executable perl or perl5 on most systems). It
is designed for general ASCII file generation with the philosophy of
embedding the Perl 5 program code into the ASCII data instead of the
usual way where you embed the ASCII data into a Perl 5 program (usually
by quoting the data and using them via "print" statements). So,
instead of writing a plain Perl script like
#!/path/to/perl
print "foo bar\n";
print "baz quux\n";
for ($i = 0; $i < 10; $i++) { print "foo #${i}\n"; }
print "foo bar\n";
print "baz quux\n";
you can write it now as an ePerl script:
#!/path/to/eperl
foo bar
baz quux
<: for ($i = 0; $i < 10; $i++) { print "foo #${i}\n"; } :>
foo bar
baz quux
Although the ePerl variant has a different source file layout, the
semantic is the same, i.e. both scripts create exactly the same
resulting data on "STDOUT".
Intention
ePerl is simply a glue code which combines the programming power of the
Perl 5 interpreter library with a tricky embedding technique. The
embedding trick is this: it converts the source file into a valid Perl
script which then gets entirely evaluated by only one internal instance
of the Perl 5 interpreter. To achieve this, ePerl translates all plain
code into (escaped) Perl 5 strings placed into print constructs while
passing through all embedded native Perl 5 code. As you can see, ePerl
itself does exactly the same internally, a silly programmer had to do
when writing a plain Perl generation script.
Due to the nature of such bristled code, ePerl is really the better
attempt when the generated ASCII data contains really more static as
dynamic data. Or in other words: Use ePerl if you want to keep the most
of the generated ASCII data in plain format while just programming some
bristled stuff. Do not use it when generating pure dynamic data. There
it brings no advantage to the ordinary program code of a plain Perl
script. So, the static part should be at least 60% or the advantage
becomes a disadvantage.
ePerl in its origin was actually designed for an extreme situation: as
a webserver scripting-language for on-the-fly HTML page generation.
Here you have the typical case that usually 90% of the data consists of
pure static HTML tags and plain ASCII while just the remaining 10% are
programming constructs which dynamically generate more markup code.
This is the reason why ePerl beside its standard Unix filtering
runtime-mode also supports the CGI/1.1 and NPH-CGI/1.1 interfaces.
Embedded Perl Syntax
Practically you can put any valid Perl constructs inside the ePerl
blocks the used Perl 5 interpreter library can evaluate. But there are
some important points you should always remember and never forget when
using ePerl:
1. Delimiters are always discarded.
Trivially to say, but should be mentioned at least once. The ePerl
block delimiters are always discarded and are only necessary for
ePerl to recognize the embedded Perl constructs. They are never
passed to the final output.
2. Generated content has to go to "STDOUT".
Although you can define subroutines, calculate some data, etc.
inside ePerl blocks only data which is explicitly written to the
"STDOUT" filehandle is expanded. In other words: When an ePerl
block does not generate content on "STDOUT", it is entirely
replaced by an empty string in the final output. But when content
is generated it is put at the point of the ePerl block in the final
output. Usually contents is generated via pure "print" constructs
which implicitly use "STDOUT" when no filehandle is given.
3. Generated content on "STDERR" always leads to an error.
Whenever content is generated on the "STDERR" filehandle, ePerl
displays an error (including the STDERR content). Use this to exit
on errors while passing errors from ePerl blocks to the calling
environment.
4. Last semicolon.
Because of the following point 6 (see below) and the fact that most
of the users don't have the internal ePerl block translations in
mind, ePerl is smart about the last semicolon. Usually every ePerl
block has to end with the semicolon of the last command.
<: cmd; ...; cmd; :>
But when the last semicolon is missing it is automatically added by
ePerl, i.e.
<: cmd; ...; cmd :>
is also correct syntax. But sometimes it is necessary to force
ePerl not to add the semicolon. Then you can add a ``"_"''
(underscore) as the last non-whitespace character in the block to
force ePerl to leave the final semicolon. Use this for constructs
like the following
<: if (...) { _:>
foo
<: } else { _:>
bar
<: } :>
where you want to spread a Perl directive over more ePerl blocks.
5. Shorthand for "print"-only blocks.
Because most of the time ePerl is used just to interpolate
variables, e.g.
<: print $VARIABLE; :>
it is useful to provide a shortcut for this kind of constructs. So
ePerl provides a shortcut via the character '='. When it
immediately (no whitespaces allowed here) follows the begin
delimiter of an ePerl block a "print" statement is implicitly
generated, i.e. the above block is equivalent to
<:=$VARIABLE:>
Notice that the semicolon was also removed here, because it gets
automatically added (see above).
6. Special EndOfLine discard command for ePerl blocks.
ePerl provides a special discard command named ``"//"'' which
discards all data up-to and including the following newline
character when directly followed an end block delimiter. Usually
when you write
foo
<: $x = 1; :>
quux
the result is
foo
quux
because ePerl always preserves code around ePerl blocks, even just
newlines. But when you write
foo
<: $x = 1; :>//
quux
the result is
foo
quux
because the ``"//"'' deleted all stuff to the end of the line,
including the newline.
7. Restrictions in parsing.
Every program has its restrictions, ePerl too. Its handicap is that
Perl is not only a rich language, it is a horrible one according to
parsing its constructs. Perhaps you know the phrase ,,Only perl can
parse Perl''. Think about it. The implication of this is that
ePerl never tries to parse the ePerl blocks itself. It entirely
relies on the Perl interpreter library, because it is the only
instance which can do this without errors. But the problem is that
ePerl at least has to recognize the begin and end positions of
those ePerl blocks.
There are two ways: It can either look for the end delimiter while
parsing but at least recognize quoted strings (where the end
delimiter gets treated as pure data). Or it can just move forward
to the next end delimiter and say that it have not occur inside
Perl constructs. In ePerl 2.0 the second one was used, while in
ePerl 2.1 the first one was taken because a lot of users wanted it
this way while using bad end delimiters like ``">"''. But actually
the author has again revised its opinion and decided to finally use
the second approach which is used since ePerl 2.2 now. Because
while the first one allows more trivial delimiters (which itself is
not a really good idea), it fails when constructs like
``"m|"[^"]+"|"'' etc. are used inside ePerl blocks. And it is
easier to escape end delimiters inside Perl constructs (for
instance via backslashes in quoted strings) than rewrite complex
Perl constructs to use even number of quotes.
So, whenever your end delimiter also occurs inside Perl constructs
you have to escape it in any way.
8. HTML entity conversion.
Because one of ePerl's usage is as a server-side scripting-language
for HTML pages, there is a common problem in conjunction with HTML
editors. They cannot know ePerl blocks, so when you enter those
blocks inside the editors they usually encode some characters with
the corresponding HTML entities. The problem is that this encoding
leads to invalid Perl code. ePerl provides the option -C for
decoding these entities which is automatically turned on in CGI
modes. See description below under option -C for more details.
Runtime Modes
ePerl can operate in three different runtime modes:
Stand-alone Unix filter mode
This is the default operation mode when used as a generation tool
from the Unix shell or as a batch-processing tool from within other
programs or scripts:
$ eperl [options] - < inputfile > outputfile
$ eperl [options] inputfile > outputfile
$ eperl [options] -o outputfile - < inputfile
$ eperl [options] -o outputfile inputfile
As you can see, ePerl can be used in any combination of STDIO and
external files. Additionally there are two interesting variants of
using this mode. First you can use ePerl in conjunction with the
Unix Shebang magic technique to implicitly select it as the
interpreter for your script similar to the way you are used to with
the plain Perl interpreter:
#!/path/to/eperl [options]
foo
<: print "bar"; :>
quux
Second, you can use ePerl in conjunction with the Bourne-Shell Here
Document technique from within you shell scripts:
#!/bin/sh
...
eperl [options] - <<EOS
foo
<: print "quux"; :>
quux
EOS
...
And finally you can use ePerl directly from within Perl programs by
the use of the Parse::ePerl(3) package (assuming that you have
installed this also; see file INSTALL inside the ePerl distribution
for more details):
#!/path/to/perl
...
use Parse::ePerl;
...
$script = <<EOT;
foo
<: print "quux"; :>
quux
EOT
...
$result = Parse::ePerl::Expand({
Script => $script,
Result => \$result,
});
...
print $result;
...
See Parse::ePerl(3) for more details.
CGI/1.1 compliant interface mode
This is the runtime mode where ePerl uses the CGI/1.1 interface of
a webserver when used as a Server-Side Scripting Language on the
Web. ePerl enters this mode automatically when the CGI/1.1
environment variable "PATH_TRANSLATED" is set and its or the
scripts filename does not begin with the NPH prefix ``nph-''. In
this runtime mode it prefixes the resulting data with HTTP/1.0
(default) or HTTP/1.1 (if identified by the webserver) compliant
response header lines.
ePerl also recognizes HTTP header lines at the beginning of the
scripts generated data, i.e. for instance you can generate your own
HTTP headers like
<? $url = "..";
print "Location: $url\n";
print "URI: $url\n\n"; !>
<html>
...
But notice that while you can output arbitrary headers, most
webservers restrict the headers which are accepted via the CGI/1.1
interface. Usually you can provide only a few specific HTTP headers
like "Location" or "Status". If you need more control you have to
use the NPH-CGI/1.1 interface mode.
Additionally ePerl provides a useful feature in this mode: It can
switch its UID/GID to the owner of the script if it runs as a Unix
SetUID program (see below under Security and the option ``u+s'' of
chmod(1)).
There are two commonly known ways of using this CGI/1.1 interface
mode on the Web. First, you can use it to explicitly transform
plain HTML files into CGI/1.1 scripts via the Shebang technique
(see above). For an Apache webserver just put the following line as
the first line of the file:
#!/path/to/eperl -mc
Then rename the script from file.html to file.cgi and set its
execution bit via
$ mv file.html file.cgi
$ chmod a+rx file.cgi
Now make sure that Apache accepts file.cgi as a CGI program by
enabling CGI support for the directory where file.cgi resides. For
this add the line
Options +ExecCGI
to the .htaccess file in this directory. Finally make sure that
Apache really recognizes the extension .cgi. Perhaps you
additionally have to add the following line to your httpd.conf
file:
AddHandler cgi-script .cgi
Now you can use file.cgi instead of file.html and make advantage of
the achieved programming capability by bristling file.cgi with your
Perl blocks (or the transformation into a CGI script would be
useless).
Alternatively (or even additionally) a webmaster can enable ePerl
support in a more seamless way by configuring ePerl as a real
implicit server-side scripting language. This is done by assigning
a MIME-type to the various valid ePerl file extensions and forcing
all files with this MIME-type to be internally processed via the
ePerl interpreter. You can accomplish this for Apache by adding the
following to your httpd.conf file
AddType application/x-httpd-eperl .phtml .eperl .epl
Action application/x-httpd-eperl /internal/cgi/eperl
ScriptAlias /internal/cgi /path/to/apache/cgi-bin
and creating a copy of the eperl program in your CGI-directory:
$ cp -p /path/to/eperl /path/to/apache/cgi-bin/eperl
Now all files with the extensions .phtml, .eperl and .epl are
automatically processed by the ePerl interpreter. There is no need
for a Shebang line or any locally enabled CGI mode.
One final hint: When you want to test your scripts offline, just
run them with forced CGI/1.1 mode from your shell. But make sure
you prepare all environment variables your script depends on, e.g.
"QUERY_STRING" or "PATH_INFO".
$ export QUERY_STRING="key1=value1&key2=value2"
$ eperl-mc file.phtml
NPH-CGI/1.1 compliant interface mode
This runtime mode is a special variant of the CGI/1.1 interface
mode, because most webservers (e.g. Apache) provide it for special
purposes. It is known as Non-Parsed-Header (NPH) CGI/1.1 mode and
is usually used by the webserver when the filename of the CGI
program is prefixed with ``"nph-"''. In this mode the webserver
does no processing on the HTTP response headers and no buffering of
the resulting data, i.e. the CGI program actually has to provide a
complete HTTP response itself. The advantage is that the program
can generate arbitrary HTTP headers or MIME-encoded multi-block
messages.
So, above we have renamed the file to file.cgi which restricted us
a little bit. When we alternatively rename file.html to
nph-file.cgi and force the NPH-CGI/1.1 interface mode via option
-mn then this file becomes a NPH-CGI/1.1 compliant program under
Apache and other webservers. Now our script can provide its own
HTTP response (it need not, because when absent ePerl provides a
default one for it).
#!/path/to/bin/eperl -mn
<? print "HTTP/1.0 200 Ok\n";
print "X-MyHeader: Foo Bar Quux\n";
print "Content-type: text/html\n\n";
<html>
...
As you expect this can be also used with the implicit Server-Side
Scripting Language technique. Put
AddType application/x-httpd-eperl .phtml .eperl .epl
Action application/x-httpd-eperl /internal/cgi/nph-eperl
ScriptAlias /internal/cgi /path/to/apache/cgi-bin
into your httpd.conf and run the command
$ cp -p /path/to/eperl /path/to/apache/cgi-bin/nph-eperl
from your shell. This is the preferred way of using ePerl as a
Server-Side Scripting Language, because it provides most
flexibility.
Security
When you are installing ePerl as a CGI/1.1 or NPH-CGI/1.1 compliant
program (see above for detailed description of these modes) via
$ cp -p /path/to/eperl /path/to/apache/cgi-bin/eperl
$ chown root /path/to/apache/cgi-bin/eperl
$ chmod u+s /path/to/apache/cgi-bin/eperl
or
$ cp -p /path/to/eperl /path/to/apache/cgi-bin/nph-eperl
$ chown root /path/to/apache/cgi-bin/nph-eperl
$ chmod u+s /path/to/apache/cgi-bin/nph-eperl
i.e. with SetUID bit enabled for the root user, ePerl can switch to the
UID/GID of the scripts owner. Although this is a very useful feature
for script programmers (because one no longer need to make auxiliary
files world-readable and temporary files world-writable!), it can be to
risky for you when you are paranoid about security of SetUID programs.
If so just don't install ePerl with enabled SetUID bit! This is the
reason why ePerl is per default only installed as a Stand-Alone Unix
filter which never needs this feature.
For those of us who decided that this feature is essential for them
ePerl tries really hard to make it secure. The following steps have to
be successfully passed before ePerl actually switches its UID/GID (in
this order):
1. The script has to match the following extensions:
.html, .phtml, .ephtml, .epl, .pl, .cgi
2. The UID of the calling process has to be a valid UID,
i.e. it has to be found in the systems password file
3. The UID of the calling process has to match the
following users: root, nobody
4. The UID of the script owner has to be a valid UID,
i.e. it has to be found in the systems password file
5. The GID of the script group has to be a valid GID,
i.e. it has to be found in the systems group file
6. The script has to stay below or in the owners homedir
IF ONLY ONE OF THOSE STEPS FAIL, NO UID/GID SWITCHING TAKES PLACE!.
Additionally (if "DO_ON_FAILED_STEP" was defined as "STOP_AND_ERROR" in
eperl_security.h - not per default defined this way!) ePerl can totally
stop processing and display its error page. This is for the really
paranoid webmasters. Per default when any step failed the UID/GID
switching is just disabled, but ePerl goes on with processing.
Alternatively you can disable some steps at compile time. See
eperl_security.h.
Also remember that ePerl always eliminates the effective UID/GID,
independent of the runtime mode and independent if ePerl has switched
to the UID/GID of the owner. For security reasons, the effective
UID/GID is always destroyed before the script is executed.
ePerl Preprocessor
ePerl provides an own preprocessor similar to CPP in style which is
either enabled manually via option -P or automatically when ePerl runs
in (NPH-)CGI mode. The following directives are supported:
"#include path"
This directive is an include directive which can be used to include
really any stuff, but was actually designed to be used to include
other ePerl source files. The path can be either a relative or
absolute path for the local filesystem or a fully qualified HTTP
URL.
In case of the absolute path the file is directly accessed on the
filesystem, while the relative path is first searched in the
current working directory and then in all directories specified via
option -I. In the third case (HTTP URL) the file is retrieves via a
HTTP/1.0 request on the network. Here HTTP redirects (response
codes 301 and 302) are supported, too.
Notice: While ePerl strictly preserves the line numbers when
translating the bristled ePerl format to plain Perl format, the
ePerl preprocessor can't do this (because its a preprocessor which
expands) for this directive. So, whenever you use "#include",
remember that line numbers in error messages are wrong.
Also notice one important security aspect: Because you can include
any stuff as it is provided with this directive, use it only for
stuff which is under your direct control. Don't use this directive
to include foreign data, at least not from external webservers. For
instance say you have a ePerl page with "#include
http://www.foreigner.com/nice-page.html" and at the next request of
this page your filesystem is lost! Why? Because the foreigner
recognizes that you include his page and are using ePerl and just
put a simple ``"<? system("rm -rf /"); !>"'' in his page. Think
about it. NEVER USE #INCLUDE FOR ANY DATA WHICH IS NOT UNDER YOUR
OWN CONTROL. Instead always use "#sinclude" for such situations.
"#sinclude path"
This is the secure variant of "#include" where after reading the
data from path all ePerl begin and end delimiters are removed. So
risky ePerl blocks lost their meaning and are converted to plain
text. Always use this directive when you want to include data which
is not under your own control.
"#if expr", "#elsif expr", "#else", "#endif"
These implement a CPP-style "#if-[#else-]#endif" construct, but
with a Perl semantic. While the other directives are real
preprocessor commands which are evaluated at the preprocessing
step, this construct is actually just transformed into a low-level
ePerl construct, so it is not actually evaluated at the
preprocessing step. It is just a handy shortcut for the following
(where BD is the currently used begin delimiter and ED the end
delimiter):
``#if expr'' -> ``BD if (expr) { _ ED//''
``#elsif expr'' -> ``BD } elsif (expr) { _ ED//''
``#else'' -> ``BD } else { _ ED//''
``#endif'' -> ``BD } _ ED//''
The advantage of this unusual aproach is that the if-condition
really can be any valid Perl expression which provides maximum
flexibility. The disadvantage is that you cannot use the if-
construct to make real preprocessing decisions. As you can see,
the design goal was just to provide a shorthand for the more
complicated Perl constructs.
"#c"
This is the comment directive which just discards all data up to
and including the newline character. Use this one to comment out
any stuff, even other preprocessor directives.
Provided Functionality
Up to know you've understand that ePerl provides a nice facility to
embed Perl code into any ASCII data. But now the typical question is:
Which Perl code can be put into these ePerl blocks and does ePerl
provide any special functionality inside these ePerl blocks?
The answers are: First, you can put really any Perl code into the ePerl
blocks which are valid to the Perl interpreter ePerl was linked with.
Second, ePerl does not provide any special functionality inside these
ePerl blocks, because Perl is already sophisticated enough ;-)
The implication of this is: Because you can use any valid Perl code you
can make use of all available Perl 5 modules, even those ones which use
shared objects (because ePerl is a Perl interpreter, including
DynaLoader support). So, browse to the Comprehensive Perl Archive
Network (CPAN) via http://www.perl.com/perl/CPAN and grab your favorite
packages which can make your life easier (both from within plain Perl
scripts and ePerl scripts) and just use the construct ``"use name;"''
in any ePerl block to use them from within ePerl.
When using ePerl as a Server-Side-Scripting-Language I really recommend
you to install at least the packages CGI.pm (currently vers. 2.36),
HTML-Stream (1.40), libnet (1.0505) and libwww-perl (5.08). When you
want to generate on-the-fly images as well, I recommend you to
additionally install at least GD (1.14) and Image-Size (2.3). The ePerl
interpreter in conjunction with these really sophisticated Perl 5
modules will provide you with maximum flexibility and functionality. In
other words: Make use of maximum Software Leverage in the hackers world
of Perl as great as possible.
OPTIONS-d name=value
Sets a Perl variable in the package "main" which can be referenced
via $name or more explicitly via $main::name. The command
eperl-d name=value ..
is actually equivalent to having
<? $name = value; !>
at the beginning of inputfile. This option can occur more than
once.
-D name=value
Sets a environment variable which can be referenced via
$ENV{'variable'} inside the Perl blocks. The command
eperl-D name=value ..
is actually equivalent to
export name=value; eperl ...
but the advantage of this option is that it doesn't manipulate the
callers environment. This option can occur more than once.
-B begin_delimiter
Sets the Perl block begin delimiter string. Use this in conjunction
with "-E" to set different delimiters when using ePerl as an
offline HTML creation-language while still using it as an online
HTML scripting-language. Default delimiters are "<?" and "!>" for
CGI modes and "<:" and ":>" for stand-alone Unix filtering mode.
There are a lot of possible variations you could choose: ""<:"" and
"":>"" (the default ePerl stand-alone filtering mode delimiters),
""<?"" and ""!>"" (the default ePerl CGI interface mode
delimiters), ""<script language='ePerl'>"" and ""</script>""
(standard HTML scripting language style), ""<script
type="text/eperl">"" and ""</script>"" (forthcoming HTML3.2+ aka
Cougar style), ""<eperl>"" and ""</eperl>"" (HTML-like style),
""<!--#eperl code='"" and ""' -->"" (NeoScript and SSI style) or
even ""<?"" and "">"" (PHP/FI style; but this no longer recommended
because it can lead to parsing problems. Should be used only for
backward compatibility to old ePerl versions 1.x).
The begin and end delimiters are searched case-insensitive.
-E end_delimiter
Sets the Perl block end delimiter string. See also option -B.
-i Forces the begin and end delimiters to be searched case-
insensitive. Use this when you are using delimiters like
``"<ePerl>"..."</ePerl>"'' or other more textual ones.
-m mode
This forces ePerl to act in a specific runtime mode. See above for
a detailed description of the three possible modes: Stand-alone
filter (mode="f", i.e. option -mf), CGI/1.1 interface mode
(mode="c", i.e. option -mc) or the NPH-CGI/1.1 interface mode
(mode="n", i.e. option -mn).
-o outputfile
Forces the output to be written to outputfile instead of STDOUT.
Use this option when using ePerl as a filter. The outputfile ``-''
sets STDOUT as the output handle explicitly. Notice that this file
is relative to the source file directory when the runtime mode is
forced to CGI or NPH-CGI.
-k Forces ePerl to keep the current working directory from where it
was started. Per default ePerl will change to the directory where
the file to be executed stays. This option is useful if you use
ePerl as an offline filter on a temporary file.
-x This sets debug mode where ePerl outputs the internally created
Perl script to the console (/dev/tty) before executing it. Only for
debugging problems with the inputfile conversion.
-I directory
Specify a directory which is both used for "#include" and
"#sinclude" directives of the ePerl preprocessor and added to @INC
under runtime. This option can occur more than once.
-P Manually enables the special ePerl Preprocessor (see above). This
option is enabled for all CGI modes automatically.
-C This enables the HTML entity conversion for ePerl blocks. This
option is automatically forced in CGI modes.
The solved problem here is the following: When you use ePerl as a
Server-Side-Scripting-Language for HTML pages and you edit your
ePerl source files via a HTML editor, the chance is high that your
editor translates some entered characters to HTML entities, for
instance ``"<"'' to ``"<"''. This leads to invalid Perl code
inside ePerl blocks, because the HTML editor has no knowledge about
ePerl blocks. Using this option the ePerl parser automatically
converts all entities found inside ePerl blocks back to plain
characters, so the Perl interpreter again receives valid code
blocks.
-L This enables the line continuation character ``"\"'' (backslash)
outside ePerl blocks. With this option you can spread oneline-data
over more lines. But use with care: This option changes your data
(outside ePerl blocks). Usually ePerl really pass through all
surrounding data as raw data. With this option the newlines become
new semantics.
-T This enabled Perl's Tainting mode where the Perl interpreter takes
special precautions called taint checks to prevent both obvious and
subtle traps. See perlsec(1) for more details.
-w This enables Warnings where the Perl interpreter produces some
lovely diagnostics. See perldiag(1) for more details.
-c This runs a pure syntax check which is similar to ``"perl -c"''.
-r This prints the internal ePerl README file to the console.
-l This prints the internal ePerl LICENSE file to the console.
-v This prints ePerl version information to the console.
-V Same as option -v but additionally shows the Perl compilation
parameters.
ENVIRONMENT
Used Variables
"PATH_TRANSLATED"
This CGI/1.1 variable is used to determine the source file when
ePerl operates as a NPH-CGI/1.1 program under the environment of a
webserver.
Provided Variables
"SCRIPT_SRC_PATH"
The absolute pathname of the script. Use this when you want to
directly access the script from within itself, for instance to do
"stat()" and other calls.
"SCRIPT_SRC_PATH_DIR"
The directory part of "SCRIPT_SRC_PATH". Use this one when you want
to directly access other files residing in the same directory as
the script, for instance to read config files, etc.
"SCRIPT_SRC_PATH_FILE"
The filename part of "SCRIPT_SRC_PATH". Use this one when you need
the name of the script, for instance for relative self-references
through URLs.
"SCRIPT_SRC_URL"
The fully-qualified URL of the script. Use this when you need a URL
for self-reference.
"SCRIPT_SRC_URL_DIR"
The directory part of "SCRIPT_SRC_URL". Use this one when you want
to directly access other files residing in the same directory as
the script via the Web, for instance to reference images, etc.
"SCRIPT_SRC_URL_FILE"
The filename part of "SCRIPT_SRC_URL". Use this one when you need
the name of the script, for instance for relative self-references
through URLs. Actually the same as "SCRIPT_SRC_PATH_FILE", but
provided for consistency.
"SCRIPT_SRC_SIZE"
The filesize of the script, in bytes.
"SCRIPT_SRC_MODIFIED"
The last modification time of the script, in seconds since 0 hours,
0 minutes, 0 seconds, January 1, 1970, Coordinated Universal Time.
"SCRIPT_SRC_MODIFIED_CTIME"
The last modification time of the script, in ctime(3) format
(``WDAY MMM DD HH:MM:SS YYYY\n'').
"SCRIPT_SRC_MODIFIED_ISOTIME"
The last modification time of the script, in ISO format
(``DD-MM-YYYY HH:MM'').
"SCRIPT_SRC_OWNER"
The username of the script owner.
"VERSION_INTERPRETER"
The ePerl identification string.
"VERSION_LANGUAGE"
The identification string of the used Perl interpreter library.
Provided Built-In Images
The following built-in images can be accessed via URL
"/url/to/nph-eperl/"NAME".gif":
"logo.gif"
The standard ePerl logo. Please do not include this one on your
website.
"powered.gif"
The ``powered by ePerl 2.2'' logo. Feel free to use this on your
website.
AUTHOR
Ralf S. Engelschall
rse@engelschall.com
www.engelschall.com
SEEALSOParse::ePerl(3), Apache::ePerl(3).
Web-References:
Perl: perl(1), http://www.perl.com/
ePerl: eperl(1), http://www.ossp.org/pkg/tool/eperl/
Apache: httpd(8), http://www.apache.org/
EN 2011-06-17 EPERL(1)
