In /usr/bin/pfbtopfa line 7: gs="`dirname \"$0\"`/$GS_EXECUTABLE" ^--------------^ SC2006: Use $(...) notation instead of legacy backticked `...`. Did you mean: gs="$(dirname \"$0\")/$GS_EXECUTABLE" In /usr/bin/pfbtopfa line 18: outfile=`basename "$1" \.pfb`.pfa ^-------------------^ SC2006: Use $(...) notation instead of legacy backticked `...`. Did you mean: outfile=$(basename "$1" \.pfb).pfa In /usr/bin/pfbtopfa line 20: echo "Usage: `basename \"$0\"` input.pfb [output.pfa]" 1>&2 ^---------------^ SC2006: Use $(...) notation instead of legacy backticked `...`. Did you mean: echo "Usage: $(basename \"$0\") input.pfb [output.pfa]" 1>&2 For more information: https://www.shellcheck.net/wiki/SC2006 -- Use $(...) notation instead of le...