Perl Function "angle brackets"

<filehandle>

Returns a line of data from the file. When reading anything in, (file, console, etc...) it is automatically split in to parts delimited by the $/ value. Note that it will ONLY RETURN ONE LINE (up to a linefeed) even if the file is in binmode if $/ is not set to something other than its default value of a linefeed. undef $/ to read the entire file in one shot with no splitting. Set $/ to an ordinal number to read a specific number of charicters each time (fixed record size)
It would appear that things like <*.txt> act as though they are opening and reading the directory listing as though it was a file using something called (I'm not making this up!) glob()

See also:

• http://www.perl.com/pub/doc/FAQs/FAQ/oldfaq-html/Q4.1.html
• http://www.perl.com/pub/doc/manual/html/pod/perlfunc/glob.html
• http://www.perl.com/pub/doc/manual/html/pod/perlop.html#I_O_Operators

Samples

reading an entire binary file (line by line) without loosing the "linefeeds" in the binary data into a variable so you can tweek it before writing it back out.

$old = $file;
$new = "$file.bak";
$bak = "$file.orig";
open(OLD, "< $old") or die "can't open $old: $!";
binmode OLD;
open(NEW, "> $new") or die "can't open $new: $!";
binmode NEW;
$mydata = "";
while (<OLD>) {
 $mydata .= $_;
 }
#now you can do stuff to $mydata;
#be sure to use s on the end of any regexps so that it will work across "lines"
#and use g on the end to replace all occurances
#e.g. s/old text/new text/sg
(print NEW $mydata) or die "can't write to $new: $!";
close(OLD);
close(NEW;
rename($old, $bak)
rename($new, $old)
 

errr... no. no. no. see perlfaq6.html i'm having trouble matching over more than one line. what's wrong which basically says that if you put in

undef $/;

you will read in the entire thing in one shot rather than line by line and binmode shouldn't matter then. Also, you can set $/ to an ORDINAL number and it will read only that number of bytes.

See:

• Opening a directory in Perl
• Perl conditions: File test conditions

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