Shell Programming and Scripting

Hi,

Can someone help with this PERL code; I am getting this error while running below code:
And this is the code:

Code:

 use File::Tail;
  $file=File::Tail->new("/some/log/file");
  while (defined($line=$file->read)) {
      print "$line";
  }

I don't usually use PERL therefore I am not familiar with PERL coding. 

All I require is to read the end of a log file and write it to another file.

Thanks

You are trying to run a Perl program as a shell script. Those errors are thrown by your shell.

Do the following:

(1) Find out the path of the "perl" interpreter on your system by using the "type" or "which" commands.

Code:

$
$ type perl
perl is hashed (/usr/bin/perl)
$
$ which perl
/usr/bin/perl
$
$

So, in my system, "perl" lies in "/usr/bin" directory.

(2) Add the shebang at the top of your Perl program, which is nothing by the characters "#!" followed by the path to perl. After adding it, your program should look like this:

Code:

$
$ cat -n PerlTestFile.pl
    1  #!/usr/bin/perl -w
    2  use File::Tail;
    3    $file=File::Tail->new("/some/log/file");
    4    while (defined($line=$file->read)) {
    5        print "$line";
    6    }
$
$

Needless to say, you'd use the path to perl on your system.

(3) Finally, to run the program, feed it to the perl interpreter, like so -

Code:

perl PerlTestFile.pl

Note that the shebang is not required if you are going to invoke your program using the "perl" interpreter, but it is a good practice. And so is the "-w" switch which prints warnings, if any.

On the other hand, if you want to run the Perl program without feeding it to the perl interpreter, then you need the shebang. And if you choose to go that way, then:

(a) keep the shebang
(b) make your file an executable:

Code:

chmod u+x PerlTestFile.pl

(c) and then call it like you would an executable -

Code:

$ ./PerlTestFile.pl

tyler_durden