opening file in perl gives errors? - perl

Question

I am writing a perl script which reads a text file (which contains absolute paths of many files one below the other), calculates the file names from abs path & then appends all file names separated by a space to the same file. So, consider a test.txt file:
D:\work\project\temp.txt
D:\work/tests/test.abc
C:/office/work/files.xyz
So after running the script the same file will contain:
D:\work\project\temp.txt
D:\work/tests/test.abc
C:/office/work/files.xyz
temp.txt test.abc files.xyz
I have this script revert.pl:
use strict;
foreach my $arg (#ARGV)
{
open my $file_handle, '>>', $arg or die "\nError trying to open the file $arg : $!";
print "Opened File : $arg\n";
my #lines = <$file_handle>;
my $all_names = "";
foreach my $line (#lines)
{
my #paths = split(/\\|\//, $line);
my $last = #paths;
$last = $last - 1;
my $name = $paths[$last];
$all_names = "$all_names $name";
}
print $file_handle "\n\n$all_names";
close $file_handle;
}
When I run the script I am getting the following error:
>> perl ..\revert.pl .\test.txt
Too many arguments for open at ..\revert.pl line 5, near "$arg or"
Execution of ..\revert.pl aborted due to compilation errors.
What is wrong over here?
UPDATE: The problem is that we are using a very old version of perl. So changed the code to:
use strict;
for my $arg (#ARGV)
{
print "$arg\n";
open (FH, ">>$arg") or die "\nError trying to open the file $arg : $!";
print "Opened File : $arg\n";
my $all_names = "";
my $line = "";
for $line (<FH>)
{
print "$line\n";
my #paths = split(/\\|\//, $line);
my $last = #paths;
$last = $last - 1;
my $name = $paths[$last];
$all_names = "$all_names $name";
}
print "$line\n";
if ($all_names == "")
{
print "Could not detect any file name.\n";
}
else
{
print FH "\n\n$all_names";
print "Success!\n";
}
close FH;
}
Now its printing the following:
>> perl ..\revert.pl .\test.txt
.\test.txt
Opened File : .\test.txt
Could not detect any file name.
What could be wrong now?

Answer 1

Perhaps you are running an old perl version, so you have to use the 2 params open version:
open(File_handle, ">>$arg") or die "\nError trying to open the file $arg : $!";
note I wrote File_handle without the $. Also, read and writting operations to the file will be:
#lines = <File_handle>;
#...
print File_handle "\n\n$all_names";
#...
close File_handle;
Update: reading file lines:
open FH, "+>>$arg" or die "open file error: $!";
#...
while( $line = <FH> ) {
#...
}