Amongst other things, the following line is in error and will cause your script to fail:

    open(FILE, '>>fai.txt') ||  die $!;
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The >> cause the file to be opened in "append" mode. You want "read" mode. You can do this to correct this:

    sub search {
        my ($file,$part_number,$revision) = @_;
        open FILE "< $file" or die "Cannot open ($file) for reading: $
+!";

        local $_;
        while (<FILE>) {
            # search line for $part_number
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Note that I have have made some changes. First, I have explicitly passed the necessary arguments to the subroutine. This makes it easier to reuse or move to a library, if necessary. Further, I've localized $_. This restricts changes to $_ to the current scope, thus ensuring that if another part of your program uses $_, you won't accidentally have a strange value in there. See perldoc -f local for more information on this.

Cheers,
Ovid

New address of my CGI Course.
Silence is Evil (feel free to copy and distribute widely - note copyright text)