In /usr/bin/debrsign line 35:
PROGNAME=`basename $0`
         ^-----------^ SC2006: Use $(...) notation instead of legacy backticked `...`.
                   ^-- SC2086: Double quote to prevent globbing and word splitting.

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


In /usr/bin/debrsign line 78:
    echo " $@"
           ^-- SC2145: Argument mixes string and array. Use * or separate argument.


In /usr/bin/debrsign line 89:
umask `perl -e 'printf "%03o\n", umask | 022'`
      ^-- SC2046: Quote this to prevent word splitting.
      ^-- SC2006: Use $(...) notation instead of legacy backticked `...`.

Did you mean: 
umask $(perl -e 'printf "%03o\n", umask | 022')


In /usr/bin/debrsign line 91:
eval $(
     ^-- SC2046: Quote this to prevent word splitting.


In /usr/bin/debrsign line 97:
      [ -r $file ] && . $file
                        ^---^ SC1090: Can't follow non-constant source. Use a directive to specify location.


In /usr/bin/debrsign line 100:
    set | egrep '^DEBRSIGN_')
          ^---^ SC2196: egrep is non-standard and deprecated. Use grep -E instead.


In /usr/bin/debrsign line 105:
    value="`echo x\"$1\" | sed -e 's/^x-.//'`"
           ^-- SC2006: Use $(...) notation instead of legacy backticked `...`.

Did you mean: 
    value="$(echo x\"$1\" | sed -e 's/^x-.//')"


In /usr/bin/debrsign line 133:
                dsc=`echo $changes | \
                    ^-- SC2006: Use $(...) notation instead of legacy backticked `...`.
                          ^------^ SC2086: Double quote to prevent globbing and word splitting.

Did you mean: 
                dsc=$(echo "$changes" | \
                    perl -pe 's/\.changes$/.dsc/; s/(.*)_(.*)_(.*)\.dsc/\1_\2.dsc/')


In /usr/bin/debrsign line 135:
                buildinfo=`echo $changes | \
                          ^-- SC2006: Use $(...) notation instead of legacy backticked `...`.
                                ^------^ SC2086: Double quote to prevent globbing and word splitting.

Did you mean: 
                buildinfo=$(echo "$changes" | \
                    perl -pe 's/\.changes$/.buildinfo/; s/(.*)_(.*)_(.*)\.buildinfo/\1_\2_\3.buildinfo/')


In /usr/bin/debrsign line 161:
        mustsetvar package "`dpkg-parsechangelog -SSource`" "source package"
                            ^----------------------------^ SC2006: Use $(...) notation instead of legacy backticked `...`.

Did you mean: 
        mustsetvar package "$(dpkg-parsechangelog -SSource)" "source package"


In /usr/bin/debrsign line 162:
        mustsetvar version "`dpkg-parsechangelog -SVersion`" "source version"
                            ^-----------------------------^ SC2006: Use $(...) notation instead of legacy backticked `...`.

Did you mean: 
        mustsetvar version "$(dpkg-parsechangelog -SVersion)" "source version"


In /usr/bin/debrsign line 179:
        sversion=`echo "$version" | perl -pe 's/^\d+://'`
                 ^-- SC2006: Use $(...) notation instead of legacy backticked `...`.
                        ^------^ SC2154: version is referenced but not assigned (did you mean 'sversion'?).

Did you mean: 
        sversion=$(echo "$version" | perl -pe 's/^\d+://')


In /usr/bin/debrsign line 180:
        pv="${package}_${sversion}"
            ^--------^ SC2154: package is referenced but not assigned.


In /usr/bin/debrsign line 185:
        if [ -n "$multiarch" -o ! -r $changes ]; then
                             ^-- SC2166: Prefer [ p ] || [ q ] as [ p -o q ] is not well defined.
                                     ^------^ SC2086: Double quote to prevent globbing and word splitting.

Did you mean: 
        if [ -n "$multiarch" -o ! -r "$changes" ]; then


In /usr/bin/debrsign line 186:
            changes=$(ls "../${package}_${sversion}_*+*.changes" "../${package}_${sversion}_multi.changes" 2>/dev/null | head -1)
                      ^-- SC2012: Use find instead of ls to better handle non-alphanumeric filenames.


In /usr/bin/debrsign line 196:
            elif [ -n "$multiarch" -a -z "$changes" ]; then
                                   ^-- SC2166: Prefer [ p ] && [ q ] as [ p -a q ] is not well defined.


In /usr/bin/debrsign line 215:
base["$changes"]=`basename "$changes"`
                 ^-------------------^ SC2006: Use $(...) notation instead of legacy backticked `...`.

Did you mean: 
base["$changes"]=$(basename "$changes")


In /usr/bin/debrsign line 216:
base["$dsc"]=`basename "$dsc"`
             ^---------------^ SC2006: Use $(...) notation instead of legacy backticked `...`.

Did you mean: 
base["$dsc"]=$(basename "$dsc")


In /usr/bin/debrsign line 217:
base["$buildinfo"]=`basename "$buildinfo"`
                   ^---------------------^ SC2006: Use $(...) notation instead of legacy backticked `...`.

Did you mean: 
base["$buildinfo"]=$(basename "$buildinfo")


In /usr/bin/debrsign line 221:
    if [ ! -f "$changes" -o ! -r "$changes" ]
                         ^-- SC2166: Prefer [ p ] || [ q ] as [ p -o q ] is not well defined.


In /usr/bin/debrsign line 230:
        if [ ! -f "$dsc" -o ! -r "$dsc" ]
                         ^-- SC2166: Prefer [ p ] || [ q ] as [ p -o q ] is not well defined.


In /usr/bin/debrsign line 241:
        if [ ! -f "$buildinfo" -o ! -r "$buildinfo" ]
                               ^-- SC2166: Prefer [ p ] || [ q ] as [ p -o q ] is not well defined.


In /usr/bin/debrsign line 256:
    withecho ssh "$remotehost" "rm -f ${base[@]}"
                                      ^--------^ SC2145: Argument mixes string and array. Use * or separate argument.


In /usr/bin/debrsign line 260:
    if [ ! -f "$dsc" -o ! -r "$dsc" ]
                     ^-- SC2166: Prefer [ p ] || [ q ] as [ p -o q ] is not well defined.


In /usr/bin/debrsign line 267:
    withecho ssh -t "$remotehost" "${DEBRSIGN_PGP_PATH}debsign $signargs $dscbase"
                                                                         ^------^ SC2154: dscbase is referenced but not assigned.

For more information:
  https://www.shellcheck.net/wiki/SC2145 -- Argument mixes string and array. ...
  https://www.shellcheck.net/wiki/SC1090 -- Can't follow non-constant source....
  https://www.shellcheck.net/wiki/SC2046 -- Quote this to prevent word splitt...