# Run command with GIT_AUTHOR_NAME, GIT_AUTHOR_EMAIL, and
 # GIT_AUTHOR_DATE exported from the current environment.
 do_with_author () {
-       GIT_AUTHOR_NAME="$GIT_AUTHOR_NAME" \
-       GIT_AUTHOR_EMAIL="$GIT_AUTHOR_EMAIL" \
-       GIT_AUTHOR_DATE="$GIT_AUTHOR_DATE" \
-       "$@"
+       (
+               export GIT_AUTHOR_NAME GIT_AUTHOR_EMAIL GIT_AUTHOR_DATE
+               "$@"
+       )
 }
 
 pick_one () {
        parent_sha1=$(git rev-parse --verify $sha1^) ||
                die "Could not get the parent of $sha1"
        current_sha1=$(git rev-parse --verify HEAD)
-       if test -z "$no_ff" -a "$current_sha1" = "$parent_sha1"
+       if test -z "$no_ff" && test "$current_sha1" = "$parent_sha1"
        then
                output git reset --hard $sha1
                output warn Fast-forward to $(git rev-parse --short $sha1)
                        sed -e 1d -e '2,/^./{
                                /^$/d
                        }' <"$SQUASH_MSG".bak
-               } >$SQUASH_MSG
+               } >"$SQUASH_MSG"
        else
                commit_message HEAD > "$FIXUP_MSG" || die "Cannot write $FIXUP_MSG"
                COUNT=2
                        echo "# The first commit's message is:"
                        echo
                        cat "$FIXUP_MSG"
-               } >$SQUASH_MSG
+               } >"$SQUASH_MSG"
        fi
        case $1 in
        squash)
                echo
                commit_message $2 | sed -e 's/^/#       /'
                ;;
-       esac >>$SQUASH_MSG
+       esac >>"$SQUASH_MSG"
 }
 
 peek_next_command () {
-       sed -n -e "/^#/d" -e "/^$/d" -e "s/ .*//p" -e "q" < "$TODO"
+       sed -n -e "/^#/d" -e '/^$/d' -e "s/ .*//p" -e "q" < "$TODO"
 }
 
 # A squash/fixup has failed.  Prepare the long version of the squash