In /usr/bin/imagetops line 22:
	FILE=`mktemp --tmpdir imagetops.XXXXXX` || exit 1
             ^-- SC2006: Use $(...) notation instead of legacy backticked `...`.

Did you mean: 
	FILE=$(mktemp --tmpdir imagetops.XXXXXX) || exit 1


In /usr/bin/imagetops line 29:
magic=`file -bi "$FILE"`
      ^----------------^ SC2006: Use $(...) notation instead of legacy backticked `...`.

Did you mean: 
magic=$(file -bi "$FILE")


In /usr/bin/imagetops line 30:
magicbase=`echo $magic | cut -f 1 -d "/"`
          ^-----------------------------^ SC2006: Use $(...) notation instead of legacy backticked `...`.
                ^----^ SC2086: Double quote to prevent globbing and word splitting.

Did you mean: 
magicbase=$(echo "$magic" | cut -f 1 -d "/")


In /usr/bin/imagetops line 31:
magictype=`echo $magic | cut -f 2- -d "/" | cut -f 1 -d ";"`
          ^-- SC2006: Use $(...) notation instead of legacy backticked `...`.
                ^----^ SC2086: Double quote to prevent globbing and word splitting.

Did you mean: 
magictype=$(echo "$magic" | cut -f 2- -d "/" | cut -f 1 -d ";")


In /usr/bin/imagetops line 61:
	exec $cmd "$FILE" | ppmtopgm | pnmtops $ARGS
                                               ^---^ SC2086: Double quote to prevent globbing and word splitting.

Did you mean: 
	exec $cmd "$FILE" | ppmtopgm | pnmtops "$ARGS"


In /usr/bin/imagetops line 63:
	exec $cmd "$FILE" | pnmtops $ARGS
                                    ^---^ SC2086: Double quote to prevent globbing and word splitting.

Did you mean: 
	exec $cmd "$FILE" | pnmtops "$ARGS"

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