In /usr/bin/ps2pdf13 line 3:
ps2pdfwr="`dirname \"$0\"`/ps2pdfwr"
          ^--------------^ SC2006: Use $(...) notation instead of legacy backticked `...`.

Did you mean: 
ps2pdfwr="$(dirname \"$0\")/ps2pdfwr"

For more information:
  https://www.shellcheck.net/wiki/SC2006 -- Use $(...) notation instead of le...