If this is really all you are doing though, you might consider putting it all on the command line. 

perl -i.bak -pe 's/pattern/replacement/'

[download]

If, however, you have decided to save your script in a file rather than just using a -e switch, then you might prefer to use the $^I special variable over the -i switch:

#!/usr/bin/perl 

$^I = ".bak"; 

while (<>) { 
    s/pattern/replacement/; 
    print;
}

[download]

That way you won't forget that you have to supply the -i and clobber a file the next time you use the script. It also allows you to make the script itself executable without losing functionality. Putting it on the shebang line does too but this approach is better in that it is more flexible. For instance, you might not want to clobber file.bak if it exists but instead write to file.bak.N (where N is a sequence number) instead. Setting $^I in the script enables you to these kind of things.

-sauoq
"My two cents aren't worth a dime.";

In reply to Re: Re: changing data by sauoq
in thread changing data by DS

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.