Search string in log.txt file

[tony75]

Hi
I try to Search for xp_cmdshell string in log.txt file but i got error?

my $file = "c:/logdata.txt";
open (IN,$file) or die "Can't read $file: $!";
my $tag = "xp_cmdshell";
open(IN,"<",$file) || die "could not open $file: $!\n";
while (<IN>) {
    if (grep(/$tag/,$_)) {
    #Do something
  }
}
Close(file);

[2teez]

Hi tony75,

1.What error message are you getting.
2.Check your filehandle "IN" you used. You can't be reading FROM and writing TO the same filehandle, like you are doing.
3.Also use a 3-arugment for open function. like

open my $fh,'<',$file_to_read or die "can't open file: $!";
   while(<$fh>){
     ...
   }
 close $fh or die "can't open file: $!";

4.Use lexically scoped filehandle like $fh in the code above.

Please see perldoc -f open frm your CLI
Hope this helps

[tony75]

Thanks Sir,
But
How can I navigate to my log.txt file on my C:\ driver ?

my $file = shift || die " Enter file name \n";
die "File not found!\n" unless (-e $file);
my $tag = "xp_cmdshell";
open(FH,"<",$file) || die "could not open $file: $!\n";
while (<FH>) {
    if (grep(/$tag/,$_)) {
    #Do something
  }
}
Close(FH);

[2teez]

Hi tony75,
Yes that should work, but you can also do like so:

#!/usr/bin/perl
use warnings;
use strict;

my $filename = "";
do {
    print "Enter  file name: ";
    ## get name from the user from CLI
    chomp( $filename = <STDIN> );
    warn "File not Found\n" if !-e $filename;
} while ( $filename eq '' or !-e $filename );

my $tag = "xp_cmdshell";

open my $fh, "<", $filename or die "could not open $filename: $!\n";
while (<$fh>) {
    chomp;
    if ( grep( /$tag/, $_ ) ) {

        #Do something
    }

}
close($fh) or die "can close file: $!";

It's good practice to always use a lexical scope filehandle like I did, than using a BAREWORD like FH, which is global as filehandles. Then always check for the return of close function just like open function.

Check the usage of the do/while, which enable the user to provide a "workable" filename from the CLI. Please note that, I didn't include a way out, except a correct filename is used. That you could do.
There are more than one way do it though.

You could also check these modules Getopt::Long or Getopt::Std. Just use perldoc Getopt::Long

[tony75]

Wonderful.
Thank you very much.