Perl question!

Shell Programming and Scripting
1

Hi All,
I am new to perl and just want to read the text file and write back it into another file with some modification.
Here is my requirement:
input file:

USB_OTG_PATH top.usb_top.otg_top
USB_HSIC_PATH top.usb_top.hsic_top
.. (All starts with USB_)
...

START_PATH USB_OTG_PATH.interrupt
START_PATH USB_HSIC_PATH.interrupt
..(All start with START_PATH)

requirement:
My output file should looks like the following
output file:

top.usb_top.otg_top.interrupt
top.usb_top.hsic_top.interrupt

Can anyone help me out to do this?

Thanks,
CS

2

Try this,

 awk 'NR==FNR{if(/^USB/){a[$1]=$2};next} a[$2]{print a[$2]"."$3}' file89 FS="[ .]" inputfile inputfile
3

Since a perlish solution was requested:

$\ = "\n";
$, = '';

while (<>) {
    chomp;

    if (my ($usb, $word) = m{^(USB\w+)\s+(.*)$}) {
        $U{$usb} = $word;
        next;
    }

    if (my ($usb, $word) = m{^START_PATH\s+(USB\w+)(\..*)$}) {
        $U{$usb} ||= '<undef>' unless defined $U{$usb};
        print $U{$usb}, $word;
    }
}