I am trying to use fork to perform a rather long task. The problem I'm having is that the child process doesn't seem to be able to access files. At least I think that's the problem. I fork using this code. It's not mine, I just grabbed it from somewhere... (die statements shortened for clarity...) 
$SIG{CHLD} = 'IGNORE'; 
defined (my $kid = fork) or die "Cannot fork: $!\n"; 
if($kid) { # do nothing... } 
else 
{
    chdir '/webRoot/cgi-bin' or die ...
    open STDIN, '/dev/null' or die ...
    open STDOUT, '>/dev/null' or die ...
    open STDERR, '>/tmp/log' or die ...
    setsid or die ...
    my $oldfh = select STDERR; 
    local $| = 1; 
    select $oldfh; 
    my $run = "perl /webRoot/apps/startPipe.pl -f $dest_file -j $job_ 
++ID -c $created -t $job_type $adv_opts"; `$run`;
    CORE::exit(0); # terminate the process 
}

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Then in the file startPipe.pl... 
for my $i (1 .. 1) 
{ 
    $arab_string .= "my \@arab$i = ("; 
    $blast_run = "blastn ATH1_chr$i.1con.01222004 $seq_file_name - +wa
+rnings"; 
    warn "$blast_run\n"; 
    $blast_output = `$blast_run`; 
    warn "Error: $!\n";
    ...

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and finally in the file /tmp/log 
blastn ATH1_chr1.1con.01222004 /webRoot/cgi-bin/jobs/15-12-2007/WZuFQe
+ +miR8sSigXB3vFjLiuix/WZuFQemiR8sSigXB3vFjLiuix -warnings 

Error: No such file or directory

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and if i copy the the string generated by $blast_run and paste it into bash it will work, the files are in the right places. I have chmodded everything to 777 to make sure that it's not permissions. I'm probably missing something very simple... Thanks.

In reply to File Access for child process by crunchi

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