Beefy Boxes and Bandwidth Generously Provided by pair Networks
Perl Monk, Perl Meditation

comment on

( #3333=superdoc: print w/replies, xml ) Need Help??

Let's say I wanted to find the word 'banana' in a file, then add a line later, such that there were three lines between the 'banana' line and my new line. I could do this:

#!/usr/bin/env perl use 5.010; use warnings; use strict; while(<DATA>){ print; # print the line if(/banana/){ # if it contained banana print scalar <DATA> for 1..3; # print the next three lines print "This line was added.\n"; # then add the new line } } # then print the rest of the +lines __DATA__ a is for apple b is for banana c is for cantaloupe d is for dill e is for elderberry f is for fennel g is for grapefruit h is for honeydew

You should be able to adapt that for your needs. For production code, you'd want to add something to handle the case where there aren't three lines between 'banana' and the end of the file, but since this looks like a homework assignment, I'll assume that's not necessary. Another improvement would be to make the search word and the number of lines to skip arguments set with variables at the top of the problem or taken from the command line. You could also write it as a subroutine which takes the input filename/filehandle, search word, and number of lines as arguments.

Aaron B.
Available for small or large Perl jobs and *nix system administration; see my home node.

In reply to Re: how to insert new line in text file after regex match? by aaron_baugher
in thread how to insert new line in text file after regex match? by sumathigokul

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

  • Are you posting in the right place? Check out Where do I post X? to know for sure.
  • Posts may use any of the Perl Monks Approved HTML tags. Currently these include the following:
    <code> <a> <b> <big> <blockquote> <br /> <dd> <dl> <dt> <em> <font> <h1> <h2> <h3> <h4> <h5> <h6> <hr /> <i> <li> <nbsp> <ol> <p> <small> <strike> <strong> <sub> <sup> <table> <td> <th> <tr> <tt> <u> <ul>
  • Snippets of code should be wrapped in <code> tags not <pre> tags. In fact, <pre> tags should generally be avoided. If they must be used, extreme care should be taken to ensure that their contents do not have long lines (<70 chars), in order to prevent horizontal scrolling (and possible janitor intervention).
  • Want more info? How to link or How to display code and escape characters are good places to start.
Log In?

What's my password?
Create A New User
Domain Nodelet?
and the web crawler heard nothing...

How do I use this? | Other CB clients
Other Users?
Others romping around the Monastery: (5)
As of 2023-06-10 13:56 GMT
Find Nodes?
    Voting Booth?
    How often do you go to conferences?

    Results (38 votes). Check out past polls.