I would test the file before STDIN: 

open(DATA, "books.txt" or die "Could not open file: $!\n";
print "Letter: " and chomp (my $letter=<STDIN>);
while(<DATA>) { print if /^$letter/io; }

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Note: mdillon is correct below: the ^ was added after his comment.

In reply to RE: Trying to make a search by turnstep
in thread Trying to make a search by zdog

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