use File::Basename

print "filename : ";

chomp(my $old_name = <stdin>);

my $dirname = dirname $old_name ;

my $basename = basename $old_name ;

$basename =~ s/^/not/ ;

my $new_name = "$dirname/$basename" ;

rename($old_name, $new_name);

-----------------------------------------------------

I have some confusion in this syntax

1) when a variable is declared in the main block only, why do we neeed to make it local ? If a variable is declared local in the main block, does it mean that if a subroutine is declared then this variable can not be used inside subroutines as its declared outside the subroutine as local ?

2) my $dirname = dirname $old_name ; # what does this syntax mean ? I have used $num = @number, to find out the number of elements in an array. I have not used any kind of name before a variable name so far.

3) s/^/not/, # does it mean that not will be added at the start of the string ?

4) (my $basename = $name =~ s#./##; # how come there is only one forward slash ?

What is the meaning of this regex ? Whenever we want to substitute values, we do =~ s/something/this/g ; there are two forward slashes in the regex. What kind of regex is this ?

In reply to Pls explain this syntax by manish.rathi

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.