The ethead routine in the wcstool package is cuurently used to assemble the initial flat file of header card values.

  

gethead -u *.fits STRUCTAZ PARANGLE PHIMOON PSYSNAME boo MILLUM

In play directory:
 ls -1 /home/sco/acm_reduced/acm/2018*fits >list.0
I edit list.0 to make an easy example file 
 
cat list.0 
/home/sco/acm_reduced/acm/20180114T013423.4_acm_sci_proc.fits
/home/sco/acm_reduced/acm/20180114T013510.1_acm_sci_proc.fits
/home/sco/acm_reduced/acm/20180403T110601.3_acm_sci_proc.fits
/home/sco/acm_reduced/acm/20180403T111010.1_acm_sci_proc.fits
/home/sco/acm_reduced/acm/20180403T111018.2_acm_sci_proc.fits

% gethead -u @list.0 STRUCTAZ PARANGLE PHIMOON PSYSNAME boo MILLUM 
20180114T013423.4_acm_sci_proc.fits 343.405525 327.377666 -99.000000 r ___ -99.000
20180114T013510.1_acm_sci_proc.fits 343.405525 327.377666 -99.000000 B ___ -99.000
20180403T110601.3_acm_sci_proc.fits 101.405994 117.124834 74.465355 g ___ 93.000
20180403T111010.1_acm_sci_proc.fits 100.670933 116.587591 70.571274 g ___ 93.000
20180403T111018.2_acm_sci_proc.fits 100.670933 116.587591 70.571198 g ___ 93.000

Notice that I include card that is never matched with anything in the headers (boo). 
% gethead -u @list.0 STRUCTAZ PARANGLE PHIMOON PSYSNAME boo MILLUM >a1
% sed 's/___/ nv /' a1 > a2
% cat a2
20180114T013423.4_acm_sci_proc.fits 343.405525 327.377666 -99.000000 r  nv  -99.000
20180114T013510.1_acm_sci_proc.fits 343.405525 327.377666 -99.000000 B  nv  -99.000
20180403T110601.3_acm_sci_proc.fits 101.405994 117.124834 74.465355 g  nv  93.000
20180403T111010.1_acm_sci_proc.fits 100.670933 116.587591 70.571274 g  nv  93.000
20180403T111018.2_acm_sci_proc.fits 100.670933 116.587591 70.571198 g  nv  93.000

Finally, note that you can dump all of your card names into afile (like the list 
of FITS image names) and make a much more compact command line: 
% cat Pnames
STRUCTAZ 
PARANGLE 
PHIMOON 
PSYSNAME 
boo 
MILLUM

% gethead -u @list.0 @Pnames 
20180114T013423.4_acm_sci_proc.fits 343.405525 327.377666 -99.000000 r ___ -99.000
20180114T013510.1_acm_sci_proc.fits 343.405525 327.377666 -99.000000 B ___ -99.000
20180403T110601.3_acm_sci_proc.fits 101.405994 117.124834 74.465355 g ___ 93.000
20180403T111010.1_acm_sci_proc.fits 100.670933 116.587591 70.571274 g ___ 93.000
20180403T111018.2_acm_sci_proc.fits 100.670933 116.587591 70.571198 g ___ 93.000