The joy of Perl(salon.com)

    $line =~ m/<some regex>/;

    $line =~ m'<some regex>';

    $line =~ /<some regex>/;

    if ($line =~ /regex/)
    {
    }

    do_something() if $line =~ /regex/;

    while(<FILE>)
    {
        chomp;
        #Do your stuff
    }

    my @file_content = `cat somefile`;

    chomp(@file_content)

    foreach my $line(@file_content)
    {
        #Do your stuff here
    }

    my @fields = split( /<some regex>/, $line );

    my @processing = map { do_something($_) } @fields;

    my @results = grep { /some regex/ } @fields;

    eval
    {
        #Some operation
    }
    if $@
    {
        #Handle exception
    }

    open( FILEHANDLE , '<' , $file ) or die "Cannot open file";

    use strict;
    use warnings;
    
    use DB_File;
    use Fcntl;

    my %some_hash
    tie (%some_hash, "DB_File", $dbm_file, O_RDONLY or die "Unable to open dbm file $dbm_file: $!";
    #change your hash
    untie(%some_hash);

    `/some/command/execute`;

    system('/some/commmand/execute');

    sub function_name
    {
        my ($var1,$var2..) = @_;

    }

    package Name;

    #do stuff here

    1;

    my $function = sub {};
    $function->();

    sub function1
    {
        my $function = sub {#does something};
        return \$function;
    }

    given($some_data_structure) #what ever that is array, reference etc
    {
        when ( #some match operation ) { #do something }
        ...
        ...
    }