In /usr/bin/mergechanges line 24:
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/mergechanges line 86:
	    echo "Unrecognised option $1.  Use $progname --help for help" >&2
                                               ^-------^ SC2154: progname is referenced but not assigned (did you mean 'PROGNAME'?).


In /usr/bin/mergechanges line 104:
    if ! test -r $f; then
                 ^-- SC2086: Double quote to prevent globbing and word splitting.

Did you mean: 
    if ! test -r "$f"; then


In /usr/bin/mergechanges line 146:
	while read line; do
              ^--^ SC2162: read without -r will mangle backslashes.


In /usr/bin/mergechanges line 201:
if test $(echo "${VERSION}" | wc -l) -ne 1; then
        ^--------------------------^ SC2046: Quote this to prevent word splitting.


In /usr/bin/mergechanges line 208:
if test $(echo "${SOURCE}" | wc -l) -ne 1; then
        ^-------------------------^ SC2046: Quote this to prevent word splitting.


In /usr/bin/mergechanges line 215:
if test $(echo "${DESCRIPTIONS}" | sed -e 's/ \+- .*$//' | uniq -d | wc -l) -ne 0; then
        ^-- SC2046: Quote this to prevent word splitting.


In /usr/bin/mergechanges line 222:
if test $(echo "${FORMATS}" | wc -l) -ne 1; then
        ^--------------------------^ SC2046: Quote this to prevent word splitting.


In /usr/bin/mergechanges line 255:
    DIR=`dirname "$1"`
        ^------------^ SC2006: Use $(...) notation instead of legacy backticked `...`.

Did you mean: 
    DIR=$(dirname "$1")


In /usr/bin/mergechanges line 266:
if $(grep -q "BEGIN PGP SIGNED MESSAGE" "$1"); then
   ^-- SC2091: Remove surrounding $() to avoid executing output.


In /usr/bin/mergechanges line 267:
    perl -ne 'next if 1../^$/; next if /^$/..1; print' "$1" > ${OUTPUT}
                                                              ^-------^ SC2086: Double quote to prevent globbing and word splitting.

Did you mean: 
    perl -ne 'next if 1../^$/; next if /^$/..1; print' "$1" > "${OUTPUT}"


In /usr/bin/mergechanges line 269:
    cp "$1" ${OUTPUT}
            ^-------^ SC2086: Double quote to prevent globbing and word splitting.

Did you mean: 
    cp "$1" "${OUTPUT}"


In /usr/bin/mergechanges line 348:
    echo "${DESCRIPTIONS}" | sed -e 's/^/ /' >> "${DESCFILE}"
    ^-- SC2001: See if you can use ${variable//search/replace} instead.

For more information:
  https://www.shellcheck.net/wiki/SC2046 -- Quote this to prevent word splitt...
  https://www.shellcheck.net/wiki/SC2091 -- Remove surrounding $() to avoid e...
  https://www.shellcheck.net/wiki/SC2154 -- progname is referenced but not as...