Perl cannot open file; from Ploteig script - perl

Question

I am a total novice when it comes to computer programming and perl, so please forgive me if this question is simple!
I am trying to run a perl script (called ploteig, a component of a free genetics program download, Eigenstrat:Eigenstrat software) that works fine until I get to line 96-
open (YY, ">$dfile") || die "can't open $dfile\n" ;
I am given the error that the file is unable to be opened and the script dies.
Below, I have provided the entire code for you (since honestly, I have no idea what part of the code could be influencing the inability to open the file). The code uses input from a file created previously with Eigenstrat, example of 4 rows, 12 columns:
#eigvals: 20.388 7.503 4.033 2.929 2.822 2.726 2.700 2.590 2.451 2.365
GREY_BI_011_COMSTOCK_11 0.0164 0.0164 0.0382 -0.1283 -0.0658 0.0406 0.0322 0.0105 -0.0851 -0.0625 Case
GREY_BI_014_COMSTOCK_14 0.0191 0.0094 0.0567 -0.0250 0.0804 -0.0531 -0.0165 0.0321 0.1130 -0.0025 Control
GREY_BI_015_COMSTOCK_15 0.0221 -0.0042 -0.0031 0.0091 0.1448 0.0351 0.0430 0.0359 0.0049 0.0791 Control
(rows represent individual sample pca scores, columns specific pcas. First column sample names, last column case or control status)
Additionally, I call the code as follows:
perl ploteig –i combogreyout.pca.evec –p Case:Control –s Out –c 1:2 –x –o utploteig.xtxt –k
I am really unsure where to go from here. I tried changing the file permissions and ensuring it was in the working directory, but it wouldn’t allow me to change permissions and everything pointed to being in the correct directory. However, I am unsure if either of these are the real problem.
I would very much appreciate any help anyone can give me!
Thank you SO much!
> #!/usr/bin/perl -w
### ploteig -i eigfile -p pops -c a:b [-t title] [-s stem] [-o outfile] [-x] [-k] [-y]
[-z sep] [-f fixgreen]
use Getopt::Std ;
use File::Basename ;
## pops : separated -x = make postscript and pdf -z use another separator
## -k keep intermediate files
## NEW if pops is a file names are read one per line
getopts('i:o:p:c:s:d:z:t:xkyf',\%opts) ;
$postscmode = $opts{"x"} ;
$oldkeystyle = $opts{"y"} ;
$kflag = $opts{"k"} ;
$keepflag = 1 if ($kflag) ;
$keepflag = 1 unless ($postscmode) ;
$dofixgreen = ( exists $opts{"f"} ? $opts{"f"} : 0 );
$zsep = ":" ;
if (defined $opts{"z"}) {
$zsep = $opts{"z"} ;
$zsep = "\+" if ($zsep eq "+") ;
}
$title = "" ;
if (defined $opts{"t"}) {
$title = $opts{"t"} ;
}
if (defined $opts{"i"}) {
$infile = $opts{"i"} ;
}
else {
usage() ;
exit 0 ;
}
open (FF, $infile) || die "can't open $infile\n" ;
#L = (<FF>) ;
chomp #L ;
$nf = 0 ;
foreach $line (#L) {
next if ($line =~ /\#/) ;
#Z = split " ", $line ;
$x = #Z ;
$nf = $x if ($nf < $x) ;
}
printf "## number of fields: %d\n", $nf ;
$popcol = $nf-1 ;
if (defined $opts{"p"}) {
$pops = $opts{"p"} ;
}
else {
die "p parameter compulsory\n" ;
}
$popsname = setpops ($pops) ;
print "$popsname\n" ;
$c1 = 1; $c2 =2 ;
if (defined $opts{"c"}) {
$cols = $opts{"c"} ;
($c1, $c2) = split ":", $cols ;
die "bad c param: $cols\n" unless (defined $cols) ;
}
$stem = "$infile.$c1:$c2" ;
if (defined $opts{"s"}) {
$stem = $opts{"s"} ;
}
$gnfile = "$stem.$popsname.xtxt" ;
if (defined $opts{"o"}) {
$gnfile = $opts{"o"} ;
}
#T = () ; ## trash
open (GG, ">$gnfile") || die "can't open $gnfile\n" ;
print GG "## " unless ($postscmode) ;
print GG "set terminal postscript color\n" ;
print GG "set title \"$title\" \n" ;
print GG "set key outside\n" unless ($oldkeystyle) ;
print GG "set xlabel \"eigenvector $c1\" \n" ;
print GG "set ylabel \"eigenvector $c2\" \n" ;
print GG "plot " ;
$np = #P ;
$lastpop = $P[$np-1] ;
$d1 = $c1+1 ;
$d2 = $c2+1 ;
foreach $pop (#P) {
$dfile = "$stem:$pop" ;
push #T, $dfile ;
print GG " \"$dfile\" using $d1:$d2 title \"$pop\" " ;
print GG ", \\\n" unless ($pop eq $lastpop) ;
chomp $dfile;
open (YY, ">$dfile") || die "can't open $dfile\n" ;
foreach $line (#L) {
next if ($line =~ /\#/) ;
#Z = split " ", $line ;
next unless (defined $Z[$popcol]) ;
next unless ($Z[$popcol] eq $pop) ;
print YY "$line\n" ;
}
close YY ;
}
print GG "\n" ;
print GG "## " if ($postscmode) ;
print GG "pause 9999\n" ;
close GG ;
if ($postscmode) {
$psfile = "$stem.ps" ;
if ($gnfile =~ /xtxt/) {
$psfile = $gnfile ;
$psfile =~ s/xtxt/ps/ ;
}
system "gnuplot < $gnfile > $psfile" ;
if ( $dofixgreen ) {
system "fixgreen $psfile" ;
}
system "ps2pdf $psfile " ;
}
unlink (#T) unless $keepflag ;
sub usage {
print "ploteig -i eigfile -p pops -c a:b [-t title] [-s stem] [-o outfile] [-x] [-k]\n" ;
print "-i eigfile input file first col indiv-id last col population\n" ;
print "## as output by smartpca in outputvecs \n" ;
print "-c a:b a, b columns to plot. 1:2 would be common and leading 2 eigenvectors\n" ;
print "-p pops Populations to plot. : delimited. eg -p Bantu:San:French\n" ;
print "## pops can also be a filename. List populations 1 per line\n" ;
print "[-s stem] stem will start various output files\n" ;
print "[-o ofile] ofile will be gnuplot control file. Should have xtxt suffix\n";
print "[-x] make ps and pdf files\n" ;
print "[-k] keep various intermediate files although -x set\n" ;
print "## necessary if .xtxt file is to be hand edited\n" ;
print "[-y] put key at top right inside box (old mode)\n" ;
print "[-t] title (legend)\n" ;
print "[-f] fix green and yellow colors\n";
print "The xtxt file is a gnuplot file and can be easily hand edited. Intermediate files
needed if you want to make your own plot\n" ;
}
sub setpops {
my ($pops) = #_ ;
local (#a, $d, $b, $e) ;
if (-e $pops) {
open (FF1, $pops) || die "can't open $pops\n" ;
#P = () ;
foreach $line (<FF1>) {
($a) = split " ", $line ;
next unless (defined $a) ;
next if ($a =~ /\#/) ;
push #P, $a ;
}
$out = join ":", #P ;
print "## pops: $out\n" ;
($b, $d , $e) = fileparse($pops) ;
return $b ;
}
#P = split $zsep, $pops ;
return $pops ;
}