I am new to Bash scripting and I need help with something.
The file bbb.txt contains many IPv4 and IPv6 addresses, like this:
10.0.2.15 fe80...
192.168.1.1 fe80...
The file aaa.txt has many iptables commands.
I want my script to find all IPv4 addresses in aaa.txt and check if they can be found in bbb.txt, when matched - IPv4 in aaa.txt is replaced with IPv6 from bbb.txt. Is it doable?
I think you're better off using perl for this:
#!/usr/bin/perl
use strict;
use warnings;
my $file1 = 'aaa.txt';
my $file2 = 'bbb.txt';
open my $if1,'<',$file1 or die "$file1: $!\n";
open my $if2,'<',$file2 or die "$file2: $!\n";
my %ip_dictionary;
while(<$if2>){
my ($ipv4,$ipv6)=split;
$ip_dictionary{$ipv4}=$ipv6;
}
close $if2;
my $slurp = do { local $/; <$if1>};
close $if1;
$slurp=~ s!((?:[0-9]{1,3}\.){3}[0-9]{1,3})!exists $ip_dictionary{$1} and is_valid_ip($1) ? $ip_dictionary{$1} : $1!eg;
open my $of,'>',$file1;
print $of $slurp;
sub is_valid_ip{
my $ip=shift//return 0;
for(split /\./,$ip){
return 0 if $_ > 255;
}
1
}
Save this to a file e.g. script.sh.
#!/bin/bash
declare -A A
while read -ra __; do
A[${__[0]}]=${__[1]}
done < "$2"
while read -r __; do
for I in "${!A[@]}"; do
[[ $__ == *"$I"* ]] && {
V=${A[$I}
__=${__//"$I"/"$V"}
}
done
echo "$__"
done < "$1"
Then run bash script.sh aaa.txt bbb.txt.
To get the output run it as something like bash script.sh aaa.txt bbb.txt > out.txt
I prefer to use Bash this time since you have to quote non-literals in Awk.
Another solution through Ruby:
ruby -e 'f = File.open(ARGV[0]).read; File.open(ARGV[1]).readlines.map{|l| l.split}.each{|a| f.gsub!(a[0], a[1])}; puts f' aaa.txt bbb.txt
Another way to modify file directly:
#!/bin/bash
A=$(<"$1")
while read -ra B; do
A=${A//"${B[0]}"/"${B[1]}"}
done < "$2"
echo "$A" > "$1"
Run as bash script.sh aaa.txt bbb.txt.
Another through Ruby:
ruby -e 'x = File.read(ARGV[0]); File.open(ARGV[1]).readlines.map{|l| l.split}.each{|a| x.gsub!(a[0], a[1])}; File.write(ARGV[0], x)' aaa.txt bbb.txt
