如何编写Perl脚本比较两个多行文本标量？忽略空格及指定行

Got it, let's put together a Perl script that meets your requirements. The core idea is to process both input strings to strip out the parts we don't care about, then compare the cleaned-up content.

Here's the complete script:

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

# Your input multi-line strings
my $string1 = <<'END_STRING';
logging on
enable secret 5 $1$okZh$nSIVWr7vNHAqk231PisjN0
snmp-server community sph1nkx5 v1default RO 5
snmp-server ifindex persist
tacacs-server timeout 5
tacacs-server key 7 xxx
END_STRING

my $string2 = <<'END_STRING';
logging on
enable secret 5 xxx
snmp-server community xxx
snmp-server ifindex persist
tacacs-server timeout 5
tacacs-server key 7 00070A160C5E190A002247
END_STRING

# Helper function to clean up the input string
sub clean_string {
    my ($input) = @_;
    my @clean_lines;
    
    # Split input into individual lines
    foreach my $line (split /\n/, $input) {
        # Skip lines starting with our target patterns (allow leading spaces)
        next if $line =~ /^\s*enable secret/;
        next if $line =~ /^\s*snmp-server community/;
        
        # Remove ALL spaces from the line
        $line =~ s/\s+//g;
        
        # Add non-empty cleaned lines to the result
        push @clean_lines, $line if $line ne '';
    }
    
    # Return cleaned lines as a sorted string (sorted to avoid line order discrepancies)
    return join("\n", sort @clean_lines);
}

# Process both strings
my $cleaned_str1 = clean_string($string1);
my $cleaned_str2 = clean_string($string2);

# Compare and output results
if ($cleaned_str1 eq $cleaned_str2) {
    print "The processed strings are identical!\n";
} else {
    print "Differences found between processed strings:\n";
    print "\n--- Cleaned String 1 ---\n$cleaned_str1\n";
    print "\n--- Cleaned String 2 ---\n$cleaned_str2\n";
}

Let's break down how this works: #

• Input Handling: We use Perl here-documents (<<'END_STRING') to safely define multi-line strings without worrying about escaping special characters.
• Cleanup Logic:
  • Split the input into lines with split /\n/ to process each line individually.
  • Skip lines that start with enable secret or snmp-server community (the ^\s* in the regex accounts for any leading spaces just in case).
  • Remove all spaces from remaining lines with s/\s+//g—this ignores spaces anywhere in the line, not just leading/trailing.
  • Filter out empty lines (in case removing spaces leaves nothing) and sort the remaining lines. Sorting ensures line order doesn't break the comparison; if you need to preserve line order for comparison, just remove the sort call.
• Comparison: We check if the cleaned, sorted strings match. If not, we print both cleaned versions to highlight exactly where the differences lie.

Example Output for Your Input: #

The script will detect the differing tacacs-server key lines and output:

Differences found between processed strings:

--- Cleaned String 1 ---
loggingon
snmp-serverifindexpersist
tacacs-serverkey7xxx
tacacs-servertimeout5

--- Cleaned String 2 ---
loggingon
snmp-serverifindexpersist
tacacs-serverkey700070A160C5E190A002247
tacacs-servertimeout5

内容的提问来源于stack exchange，提问作者Rudraprasad Pradhan