perl中heredoc

在成块打印文本的时候特别有用。

格式

print <<EOF

you text go here

EOF

sub usage{
    print <<EOF;
Usage: test.pl -c config, -f file -l lines
    -c config file
    -f file name
    -l number of lines
EOF
}

NOTE: the last EOF must start at the beginning of the line!!!

you can use other words instead of EOF