| During an earlier project (Perl - processing
HTML) I developed a Perl script html_mklinks.pl which
processes HTML format input files. This was
originally developed under Linux, and was used to
process the HTML files which make up this site,
to ensure the hyperlinks are kept up to date. I
had to close down Windows and restart Linux just
to run the Perl script. What I needed was a
Windows version of Perl. I came across just what
I was looking for on a CD supplied with the May
2000 edition of PC
Plus magazine - ActivePerl. This was based on
version 5 of Perl (just like my installed Linux
version). ActivePerl installed easily via a
self-extracting executable containing an
InstallShield-type package. Using the default
options it installed into a perl directory on the
C drive, including html documentation. This
consisted of three separate products . So far, I
have only looked at the first:
- Perl for Win32 - Perl interpreter and
libraries and utilities used by the other
products
- Perl for ISAPI - A plug-in designed to
run Perl scripts faster on ISAPI
compliant Web servers
- Perl for ActiveX - An ActiveX scripting
engine - this allows Perl-like code
fragments to be embedded in other script
languages, using a tag <SCRIPT
LANGUAGE="PerlScript">..
The installation process updated the Windows
system files to include the Perl utilities. After
a reboot, I was able to start a DOS session and
run Perl scripts as suggested in the PC Plus
article, for example:
perl myprog.perl
In other words, I was close to being able to
run html_mklinks.pl,
the Perl script earlier developed under Linux. I
wanted to be able to run the script with
arguments and use pattern-matching as in the
Linux shell (currently the default shell, bash).
How was this to be achieved ? I hit on the idea
of wrapping the HTML processing in another Perl
script, html_files.pl,
which uses Perl regular expressions for pattern
matching, to select the files to be processed.
This in turn gave me an idea for another project
- to write a general purpose script to run
commands with options and arguments within DOS.
Before digressing too far, its worth noting
that the only changes needed to my Perl scripts
to work under DOS were those connected with
running external commands. Clearly, references to
Linux commands such as `ls [0-9]*.html` were not
going to work! This was easily fixed by changing
the scripts to open and read directories entries,
using "grep" to filter the resulting
Perl arrays, and "sort" to order the
results. In the course of this, I discovered the
"-d" option which runs a Perl debugger
- for anyone used to command line debugging, this
should hold no fears.
So I had achieved my goal of implementing a
Perl environment to run portable scripts.
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