Solved

Perl For Each Line

Posted on 2014-02-23
6
501 Views
Last Modified: 2014-02-24
I am trying to eventually do more with each line, but at the moment, I am trying to print each line of a file. I seem to be doing something wrong though, as nothing gets printed. I was trying to load the file into an array, and then use each line to do various tasks.

$filename = "file.log";

my @lines = do {
    open my $fh, "<", $filename
        or die "could not open $filename: $!";
    <$fh>;
};

my @lines = split /\n/, $str;
foreach my $line (@lines) {
print "$line \n";
}
0
Comment
Question by:stakor
  • 3
  • 2
6 Comments
 
LVL 4

Expert Comment

by:pcmghouse
ID: 39880546
$retval = open(myinputfile, "<file.log");
if($retval ne 1)
{
      printf(logfile "Unable to open the file\n");
      exit
}

while(!eof(myinputfile))
{
      $mychar = getc(myinputfile);
      if($mychar eq "\n")
      {
        print "$line \n"
                  }
        else
      {
        $line = join('',$line,$mychar)
      }
}
close(myinputfile)
0
 
LVL 84

Accepted Solution

by:
ozo earned 500 total points
ID: 39880565
my @lines = do {
    open my $fh, "<", $filename
        or die "could not open $filename: $!";
    <$fh>;
};
foreach my $line (@lines) {
print "$line \n";
}

#or

my $str = do {
    local $/;
    open my $fh, "<", $filename
        or die "could not open $filename: $!";
    <$fh>;
};
my @lines = split /\n/, $str;
foreach my $line (@lines) {
print "$line \n";
}

#or

open my $fh, "<", $filename
        or die "could not open $filename: $!";
for( <$fh> ){
  print;
}

# or

open my $fh, "<", $filename
        or die "could not open $filename: $!";
while( <$fh> ){
  print;
}

#or

{local @ARGV=($filename);
  while( <> ){
     print;
  }
}
0
 

Author Comment

by:stakor
ID: 39881155
When I used the first example, it opened the file, and read the contents, but when it printed the results out, it seemed to do so all on one line. When I added extra 'new lines' to the end of the print statement, it was still the same.
0
Is Your Active Directory as Secure as You Think?

More than 75% of all records are compromised because of the loss or theft of a privileged credential. Experts have been exploring Active Directory infrastructure to identify key threats and establish best practices for keeping data safe. Attend this month’s webinar to learn more.

 
LVL 84

Expert Comment

by:ozo
ID: 39881432
Sorry, I didn't notice the "\n", which would be necessary in the
my @lines = split /\n/, $str;
version, but not in the other versions.
0
 

Author Comment

by:stakor
ID: 39881829
Sorry that comment was for pcmghouse's solution. I am using:

my @lines = do {
    open my $fh, "<", $filename
        or die "could not open $filename: $!";
    <$fh>;
};
foreach my $line (@lines) {
print "$line \n";
}
0
 
LVL 84

Expert Comment

by:ozo
ID: 39881839
print "$line \n";
is fine if you want to add a extra space and newline after each line, otherwise, just
print $line;
should suffice.
0

Featured Post

Is Your Active Directory as Secure as You Think?

More than 75% of all records are compromised because of the loss or theft of a privileged credential. Experts have been exploring Active Directory infrastructure to identify key threats and establish best practices for keeping data safe. Attend this month’s webinar to learn more.

Question has a verified solution.

If you are experiencing a similar issue, please ask a related question

Many time we need to work with multiple files all together. If its windows system then we can use some GUI based editor to accomplish our task. But what if you are on putty or have only CLI(Command Line Interface) as an option to  edit your files. I…
A year or so back I was asked to have a play with MongoDB; within half an hour I had downloaded (http://www.mongodb.org/downloads),  installed and started the daemon, and had a console window open. After an hour or two of playing at the command …
Explain concepts important to validation of email addresses with regular expressions. Applies to most languages/tools that uses regular expressions. Consider email address RFCs: Look at HTML5 form input element (with type=email) regex pattern: T…
Migrating to Microsoft Office 365 is becoming increasingly popular for organizations both large and small. If you have made the leap to Microsoft’s cloud platform, you know that you will need to create a corporate email signature for your Office 365…

911 members asked questions and received personalized solutions in the past 7 days.

Join the community of 500,000 technology professionals and ask your questions.

Join & Ask a Question

Need Help in Real-Time?

Connect with top rated Experts

18 Experts available now in Live!

Get 1:1 Help Now