This subdirectory contains extra utilities that I'm convinced users will find
useful, but are perhaps not quite ready for global use.  They are compiled by
default, but not installed.

To install these extra utilities, type "make install-extra" from the main
littleutils directory, or type "make install" from this directory.  A
description of the extra utilities follows:

  pren - rename files using Perl regular expressions

    [Why is pren not a regular littleutil?  I'm concerned about security.  The
    pren utility uses the perl "eval" command to bring in regular expression
    information from the command line.  It *may* be possible that a
    maliciously-crafted "regex" could cause the pren utility to do something
    else besides rename files.  Not sure.  Because I'm not sure, pren will live
    in the extra subdir for now.]

  to-7zip - converts .Z (compress), .gz (gzip), and .bz2 (bzip2) files to .7z
            (p7zip)

    [Why is to-7zip not a regular littleutil?  It definitely has security risks
    when used in a world-writable directory such as /tmp.  I'd planned to fix
    this with the tempfile utility, but 7za (part of the p7zip package) very
    annoyingly refuses to overwrite a zero-length file, thus breaking the
    scheme.  If it did the overwrite properly, the strategy used in to-bzip2
    (found in the scripts directory) could be used.  As it stands, the
    randomization technique used in to-7zip makes it very difficult to perform
    a symlink attack, but not impossible.  Also, the 7za program used as the
    compression engine inside to-7zip traps signals in an unusual manner and
    keeps <ctrl-C> from interrupting things properly.  No work-around has
    presented itself thus far.]

  opt-pdf - runs PDF files through Ghostscript

    [Why is opt-pdf not a regular littleutil?  It's somewhat new (created in
    Aug of 2013) and still feels less than fully mature.  I need to play with
    it more before releasing it on the general public.

  pdfidiff - show the differences between two PDF files in a third PDF

    [Why is pdfidiff not a regular littleutil?  It's also quite new (created in
    Dec of 2018) and is definitely less than fully mature.  It also needs
    exercise before a full public release.]

  pdfquant - reduce the bitmap of scanned images inside PDF files

    [Why is pdfquant not a regular littleutil?  It's quite new (created in Mar
    of 2021) and is definitely less than fully mature.  It also needs exercise
    before a full public release.]

  pdfbw4 - reduce scanned images inside PDF files to strictly black-and-white

    [Why is pdfbw4 not a regular littleutil?  It's very new (created in Mar of
    2025) and is definitely less than fully mature.  It also needs exercise
    before a full public release.]
