Ah, fellow monks, I am a depraved regex junky. I just cant get enough and find myself coding them for the heck of it. Is there help for me? But, I digress. Let us examine this code: 
    my ($ptid, $total, $used, $avail, $pct, $mp) = $element =~
      m!^(/dev/.+[0-9]+)      # which partition $ptid
          \s+([0-9.]+[MGK])   # total size of parition $total
          \s+([0-9.]+[MGK])   # used space $used
          \s+([0-9.]+[MGK])   # available space $avail
          \s+(\d{2})%         # percent usage $pct
          \s+(.*)$!x;         # mounting point $mp

[download]
This regex is being used to match this data: 
----
Sat Feb 3 12:01:01 EST 2001
Filesystem            Size  Used Avail Use% Mounted on
/dev/hda7             904M  261M  598M  30% /
/dev/hda12            852M  378M  474M  44% /devel
/dev/hda10            9.8G  9.6G  256M  97% /home
/dev/hda9             1.8G  1.6G  225M  88% /home/dl
/dev/hda5             768M  751M   17M  98% /mnt/macos
/dev/hda8             3.9G  3.4G  304M  92% /usr
/dev/hda6             387M   93M  275M  25% /var
/dev/hdb5            1008M  591M  365M  62% /home/ftp
/dev/hdb6            1008M  209M  748M  22% /home/httpd
/dev/hdb9             1.5G  1.1G  358M  75% /mnt/build
/dev/hdb8             640M  456M  151M  75% /mnt/mp3

[download]
which is being repeated on an hourly cronjob. So this could easily turn into several megs (or even dozens of megs) of text. Therefore, speed will be an issue.

So I'm looking at this and see a pretty specific regex. I thought of substituting \S+ for .*. However, in unix (nt compatibility, obviously, is not an issue here) mounting points can include awful characters like *, \n, \a, and so on. So, basically, I see two flaws to the expression. First, the use of .* (and .+), and second the part where \s+([0-9.]+[MGK]) is captured seems repetitive. Has anyone got some regex-tuning hints here?

thanks,
brother dep.

--
i am not cool enough to have a signature.

In reply to Getting rid of (.*) from a not-quite-complex regex. by deprecated

Title:
Use:  <p> text here (a paragraph) </p>
and:  <code> code here </code>
to format your post, it's "PerlMonks-approved HTML":


  • Posts are HTML formatted. Put <p> </p> tags around your paragraphs. Put <code> </code> tags around your code and data!
  • Titles consisting of a single word are discouraged, and in most cases are disallowed outright.
  • Read Where should I post X? if you're not absolutely sure you're posting in the right place.
  • Please read these before you post! —
  • Posts may use any of the Perl Monks Approved HTML tags:
    a, abbr, b, big, blockquote, br, caption, center, col, colgroup, dd, del, details, div, dl, dt, em, font, h1, h2, h3, h4, h5, h6, hr, i, ins, li, ol, p, pre, readmore, small, span, spoiler, strike, strong, sub, summary, sup, table, tbody, td, tfoot, th, thead, tr, tt, u, ul, wbr
  • You may need to use entities for some characters, as follows. (Exception: Within code tags, you can put the characters literally.)
            For:     Use:
    & &amp;
    < &lt;
    > &gt;
    [ &#91;
    ] &#93;
  • Link using PerlMonks shortcuts! What shortcuts can I use for linking?
  • See Writeup Formatting Tips and other pages linked from there for more info.