FileCache



FileCache

NAME
SYNOPSIS
DESCRIPTION
CAVEATS
BUGS

NAME

FileCache − keep more files open than the system permits

SYNOPSIS

    no strict 'refs';
    use FileCache;
    # or
    use FileCache maxopen => 16;
    cacheout $mode, $path;
    # or
    cacheout $path;
    print $path @data;
    $fh = cacheout $mode, $path;
    # or
    $fh = cacheout $path;
    print $fh @data;

DESCRIPTION

The "cacheout" function will make sure that there’s a filehandle open for reading or writing available as the pathname you give it. It automatically closes and re-opens files if you exceed your system’s maximum number of file descriptors, or the suggested maximum maxopen.
cacheout EXPR

The 1−argument form of cacheout will open a file for writing ('>') on it’s first use, and appending ('>>') thereafter.

Returns EXPR on success for convenience. You may neglect the return value and manipulate EXPR as the filehandle directly if you prefer.

cacheout MODE, EXPR

The 2−argument form of cacheout will use the supplied mode for the initial and subsequent openings. Most valid modes for 3−argument "open" are supported namely; '>', '+>', '<', '<+', '>>', '|−' and '−|'

To pass supplemental arguments to a program opened with '|−' or '−|' append them to the command string as you would system EXPR.

Returns EXPR on success for convenience. You may neglect the return value and manipulate EXPR as the filehandle directly if you prefer.

CAVEATS

While it is permissible to "close" a FileCache managed file, do not do so if you are calling "FileCache::cacheout" from a package other than which it was imported, or with another module which overrides "close". If you must, use "FileCache::cacheout_close".

Although FileCache can be used with piped opens (’−|’ or ’|−’) doing so is strongly discouraged. If FileCache finds it necessary to close and then reopen a pipe, the command at the far end of the pipe will be reexecuted − the results of performing IO on FileCache’d pipes is unlikely to be what you expect. The ability to use FileCache on pipes may be removed in a future release.

FileCache does not store the current file offset if it finds it necessary to close a file. When the file is reopened, the offset will be as specified by the original "open" file mode. This could be construed to be a bug.

The module functionality relies on symbolic references, so things will break under ’use strict’ unless ’no strict "refs"’ is also specified.

BUGS

sys/param.h lies with its "NOFILE" define on some systems, so you may have to set maxopen yourself.







Opportunity


Personal Opportunity - Free software gives you access to billions of dollars of software at no cost. Use this software for your business, personal use or to develop a profitable skill. Access to source code provides access to a level of capabilities/information that companies protect though copyrights. Open source is a core component of the Internet and it is available to you. Leverage the billions of dollars in resources and capabilities to build a career, establish a business or change the world. The potential is endless for those who understand the opportunity.

Business Opportunity - Goldman Sachs, IBM and countless large corporations are leveraging open source to reduce costs, develop products and increase their bottom lines. Learn what these companies know about open source and how open source can give you the advantage.





Free Software


Free Software provides computer programs and capabilities at no cost but more importantly, it provides the freedom to run, edit, contribute to, and share the software. The importance of free software is a matter of access, not price. Software at no cost is a benefit but ownership rights to the software and source code is far more significant.


Free Office Software - The Libre Office suite provides top desktop productivity tools for free. This includes, a word processor, spreadsheet, presentation engine, drawing and flowcharting, database and math applications. Libre Office is available for Linux or Windows.





Free Books


The Free Books Library is a collection of thousands of the most popular public domain books in an online readable format. The collection includes great classical literature and more recent works where the U.S. copyright has expired. These books are yours to read and use without restrictions.


Source Code - Want to change a program or know how it works? Open Source provides the source code for its programs so that anyone can use, modify or learn how to write those programs themselves. Visit the GNU source code repositories to download the source.





Education


Study at Harvard, Stanford or MIT - Open edX provides free online courses from Harvard, MIT, Columbia, UC Berkeley and other top Universities. Hundreds of courses for almost all major subjects and course levels. Open edx also offers some paid courses and selected certifications.


Linux Manual Pages - A man or manual page is a form of software documentation found on Linux/Unix operating systems. Topics covered include computer programs (including library and system calls), formal standards and conventions, and even abstract concepts.