Welcome to the Monastery.

Attacking your problem should have 3 steps: "How do I read a file?", "How do substitutions on a string?" and "How do I output the result?". For the first, you'll likely want to use open and read, for the second you'll want to use a regular expression and then lastly you'll want to use print statements. A sample code follows, though you could certainly create more succinct and faster code one you gain familiarity:

use strict;
use warnings;

# Read data into an array
open my $fh, "<", "input.txt";
my @strings = ();
while (my $line = <$fh>) {
    chomp $line;
    push @strings, $line;
}
close $fh;

# Replace trailing _in and _out
foreach my $line (@strings) {
    $line =~ s/\_in$|\_out$//;
}

# Output to STDOUT
foreach my $line (@strings) {
    print $line, "\n";
}

[download]

In reply to Re: read few alphabets from a given data by kennethk
in thread read few alphabets from a given data by sharan

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.