A simple regex works fine, but transliteration is often more efficient. Here's an approach with tr///. This snippet iterates over each line of each file supplied at the command prompt, and prints the filename and line number, along with a highlighted version of the line's data showing where the problems are:

while( <> ) {
  chomp;
  if( tr/IMO//c ) {
    s/([^IMO]+)/[-->$1<--]/g;
    print "File: $ARGV, Line $.: $_\n";
  }
}

[download]

This would be invoked as:

$ ./nonimo.pl filename1.txt filename2.txt

It could be expressed as a one-liner, in fact, like this:

perl -lnE 'if(tr/IMO//c){s/([^IMO]+)/[-->$1<--]/g; say "$ARGV-$.: $_"}
+' file1.txt file2.txt fileXX.txt

[download]

The output is a little more terse, but it does the same thing. In either case, if your objective is just to print the bad lines, you can easily simplify the print statement.


Dave

In reply to Re: what regular expression do I need? by davido
in thread what regular expression do I need? by Anonymous Monk

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.