This subdirectory contains extra utilities that I believe 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 and/or Poppler

    [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.]
