I am trying to combine two kinds of files(afile and bfile),and make it into one file,so I write a.pl to do the work and use the shell script to finish the whole process,for both afiles and bfiles have 1000 pieces.
but when i run it,it returns "
/a/afile_002:cannot execute binary file
/b/bfile_002:cannot execute binary file
"
(afile and bfile don't have any extension names)
the a.pl is like following:

#! /usr/bin/perl

if (@ARGV != 2) {
my $help = << "end_of_help;";
Usage: a.pl <afile> <bfile>
end_of_help;
print $help;
exit;
}

my $afile = shift @ARGV;
my $bfile = shift @ARGV;


open A, "$afile" or die "error opening afile! $!\n";

open B, "$afile" or die "error opening afile! $!\n";

while($str1=<$afile>&&$str2=<$bfile>){

$string=$string.$str1;
$string=$string.$str2;

}

print $string;

And the shell script is:
i=1
pbfile=""
tbfile=""

while test $i -lq 1000
do
if test $i -le 10
then
$bfile '/b/b_00'$i''
$afile '/a/a_00'$i''

elif test $i -lt 100
then
$bfile '/b/b_0$i'
$afile '/a/a_0$i'

elif test $i -lt 1000
then
$bfile '/b/b_$i'
$afile '/a/a_$i'

fi

/usr/bin/perl /perl/bin/a.pl $afile $bfile

((i=$i+1))
done

You don't actually define the values for $afile, $bfile before using in the shell file here:
$bfile '/b/b_00'$i''
$afile '/a/a_00'$i''

I suspect there's more to this than you show.

Actually I made
"$bfile="/b/b_00i"
$afile="/a/a_00$i"
at first.but it says "=/a/a_001:file or directory not exsist"
so I tried to change it this way ,
it just said"afile:cannot execute binary file".
do I make it clear?

Not precisely on your question, but I think that unless the files have the same number of lines, then the while loop in your perl script will miss the last lines of the longer file will not appear in the output.

in fact I intended to build the final file according to the shorter file,that is if afile has less lines,then when afile is over, so is the final file.

now I can partly handle this problem.
but I now face another one when I try to export the final file which combine afile and bfile.
Do you friends have any ideas that how can I change my shell script,so that I can make it.
by the way ,I am using the bash.

Please show us the code and explain what you mean by 'export the file'?

a.pl and the shell script have been showed in the thread,aren't they?
export the results means, I want to create the cfile_001,for example, which combines afile_001 and bfile_001,and so from 001 to 1000,I can get 1000 cfiles.