How to preserve trailing spaces on perl variables? - perl

Question

Script (originally copied from here) takes a fixed-width text file as input, rearranges the order of columns, and should output a fixed-width text file. But trailing spaces are being truncated from the variables, which means the output isn't fixed-width.
open(INPUT, "</home/ecom/tmp/citiBIG/GROUP.txt");
open(OUTPUT, ">/home/ecom/tmp/citiBIG/GROUP2.txt");
my $LINEFORMAT = "A2 A7 A14 A4 A2 A2 A4 A12 A25 A30 A26 A40 A40 A40 A25 A4 A12 A14 A2 A8 A12 A70 A8"; # Adjust to your
field widths
while(<INPUT>) {
chomp;
my($Null0, $EmpNum, $CcNumber, $Null1, $CcExpYy, $CcExpMm, $Null2, $Title, $LastName, $FirstName, $HolderName, $Ad
dress1, $Address2, $Address3, $Suburb, $State, $PostCode, $Null3, $AreaCode, $WorkPhone, $Null4, $Email, $GroupName) =
unpack($LINEFORMAT, $_);
print OUTPUT $EmpNum . " " . "~" . $LastName . "~" . $FirstName . "~" . $Title . " " . "~" .
$Address1 . "~" . $Address2 . "~" . $Address3 . "~" . $Suburb . "~" . $PostCode . "~" . $State . "~" . $AreaCode . "~"
. $WorkPhone . "~" . $CcNumber . "~" . $CcExpMm . "~" . $CcExpYy . "~" . $HolderName . "~" . $Email . "~" . $GroupNam
e . " " . "~" . "\n";
}
close INPUT;
close OUTPUT;

Answer 1

perldoc -f pack suggests:
o The "a", "A", and "Z" types gobble just one value, but pack
it as a string of length count, padding with nulls or
spaces as needed. When unpacking, "A" strips trailing
whitespace and nulls, "Z" strips everything after the first
null, and "a" returns data without any sort of trimming.
Maybe you could try "a" instead of "A" in the format string? Alternatively you could use printf to pad the output fields to the desired widths.