In /usr/bin/dscextract line 44:
shift $(($OPTIND - 1))
         ^-----^ SC2004: $/${} is unnecessary on arithmetic variables.


In /usr/bin/dscextract line 46:
[ $# = 2 ] || die "Usage: $(basename $0) <dsc> <file>"
                                     ^-- SC2086: Double quote to prevent globbing and word splitting.

Did you mean: 
[ $# = 2 ] || die "Usage: $(basename "$0") <dsc> <file>"


In /usr/bin/dscextract line 55:
if DIFFGZ=$(egrep '^ [0-9a-f]{32,64} [0-9]+ [^ ]+\.diff\.(gz|xz|lzma|bz2)$' "$DSC") ; then
            ^---^ SC2196: egrep is non-standard and deprecated. Use grep -E instead.


In /usr/bin/dscextract line 63:
			ORIGTGZ=$(egrep '^ [0-9a-f]{32,64} [0-9]+ [^ ]+\.orig\.tar\.(gz|xz|lzma|bz2)$' "$DSC") || die "no orig.tar.* found in $DSC"
                                  ^---^ SC2196: egrep is non-standard and deprecated. Use grep -E instead.


In /usr/bin/dscextract line 65:
			setzip $ORIGTGZ
                               ^------^ SC2086: Double quote to prevent globbing and word splitting.

Did you mean: 
			setzip "$ORIGTGZ"


In /usr/bin/dscextract line 80:
if DEBIANTARGZ=$(egrep '^ [0-9a-f]{32,64} [0-9]+ [^ ]+\.debian\.tar\.(gz|xz|lzma|bz2)$' "$DSC") ; then
                 ^---^ SC2196: egrep is non-standard and deprecated. Use grep -E instead.


In /usr/bin/dscextract line 85:
			setzip $DEBIANTARGZ
                               ^----------^ SC2086: Double quote to prevent globbing and word splitting.

Did you mean: 
			setzip "$DEBIANTARGZ"


In /usr/bin/dscextract line 94:
			ORIGTGZ=$(egrep '^ [0-9a-f]{32,64} [0-9]+ [^ ]+\.orig\.tar\.(gz|xz|lzma|bz2)$' "$DSC") || die "no orig.tar.gz found in $DSC"
                                  ^---^ SC2196: egrep is non-standard and deprecated. Use grep -E instead.


In /usr/bin/dscextract line 97:
			setzip $ORIGTGZ
                               ^------^ SC2086: Double quote to prevent globbing and word splitting.

Did you mean: 
			setzip "$ORIGTGZ"


In /usr/bin/dscextract line 108:
if TARGZ=$(egrep '^ [0-9a-f]{32,64} [0-9]+ [^ ]+\.tar\.(gz|xz|lzma|bz2)$' "$DSC") ; then
           ^---^ SC2196: egrep is non-standard and deprecated. Use grep -E instead.


In /usr/bin/dscextract line 111:
	setzip $TARGZ
               ^----^ SC2086: Double quote to prevent globbing and word splitting.

Did you mean: 
	setzip "$TARGZ"

For more information:
  https://www.shellcheck.net/wiki/SC2086 -- Double quote to prevent globbing ...
  https://www.shellcheck.net/wiki/SC2196 -- egrep is non-standard and depreca...
  https://www.shellcheck.net/wiki/SC2004 -- $/${} is unnecessary on arithmeti...