In /usr/bin/pdf2dsc line 11:
gs="`dirname \"$0\"`/$GS_EXECUTABLE"
    ^--------------^ SC2006: Use $(...) notation instead of legacy backticked `...`.

Did you mean: 
gs="$(dirname \"$0\")/$GS_EXECUTABLE"


In /usr/bin/pdf2dsc line 17:
me=`basename $0`
   ^-----------^ SC2006: Use $(...) notation instead of legacy backticked `...`.
             ^-- SC2086: Double quote to prevent globbing and word splitting.

Did you mean: 
me=$(basename "$0")


In /usr/bin/pdf2dsc line 20:
    >&2 echo usage: $me "pdffile [ dscfile ]"
                    ^-^ SC2086: Double quote to prevent globbing and word splitting.

Did you mean: 
    >&2 echo usage: "$me" "pdffile [ dscfile ]"


In /usr/bin/pdf2dsc line 31:
: ${dscfile:=`echo $pdffile | sed 's,\.[^/.]*,,'`.dsc}
  ^-- SC2223: This default assignment may cause DoS due to globbing. Quote it.
             ^-- SC2006: Use $(...) notation instead of legacy backticked `...`.
                   ^------^ SC2086: Double quote to prevent globbing and word splitting.

Did you mean: 
: ${dscfile:=$(echo "$pdffile" | sed 's,\.[^/.]*,,').dsc}

For more information:
  https://www.shellcheck.net/wiki/SC2086 -- Double quote to prevent globbing ...
  https://www.shellcheck.net/wiki/SC2223 -- This default assignment may cause...
  https://www.shellcheck.net/wiki/SC2006 -- Use $(...) notation instead of le...