perl中heredoc使用说明

格式

print <<EOF
you text go here
EOF

代码如下:
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