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Hi all,
I am a perl newbie, who is learning perl because I accidentally became a
sysadmin at work (sigh). My first task was a set of perl scripts to change
entries in .hosts files for BIND/DNS. The first one I wrote only needed to
change the TTL value in the file, and so I kinda munged it by using, in part:
if ($line=~/\)$/) {
print FILEOUT " $ttl )\n";
Now I need to write one that will update the IP address, wherever it is
given. Assuming that I have two variables $IPold and $IPnew, how would I
write a regex to replace the one above that will find all instances of $IPold
in a variable $line, and replace them with $IPnew?
Here is some more code to put it in context:
#!/usr/bin/perl
use strict
my $dir= shift || '.'; # work only in the dir it is called from
print "--==++ Update MX records ++==--\n";
print "Enter old IP: ";
my $IP1=<STDIN>;
print "Enter new IP: ";
my $IP2=<STDIN>;
chomp $IP1; # remove newline chars
chomp $IP2; # remove newline chars
opendir(DIR, $dir) or die "Cannot open $dir for reading: $!\n";
for my $file (grep(!/^\.\.?$/, readdir(DIR))) {
chomp $file;
next unless ($file =~ /\.hosts$/);
open (FILEOUT, ">$dir/${file}.jonnew") or die "Cannot open
$dir/${file}.jonnew for writing: $!\n";
open (FILEIN, "$dir/$file") or die "Cannot open $dir/$file for reading:
$!\n";
my $changed = 0;
while (my $line = <FILEIN>) {
chomp ($line);
$line =~ s/\r$//;
if ($line=~/mail IN A $IP1/) {
print FILEOUT "mail IN A $IP2\n";
$changed++;
} else {
print FILEOUT "$line\n";
}
}
close (FILEIN);
close (FILEOUT);
if ($changed) {
unlink("$dir/$file");
link("$dir/${file}.jonnew", "$dir/$file");
unlink("$dir/${file}.jonnew");
} else {
unlink("$dir/${file}.jonnew");
}
}
closedir(DIR);
- --
Jon Tillman
http://www.eruditum.org
The worst thing about censorship is
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