fix: prevent displaying confusing ``diff`` output when file is already existing and different

Signed-off-by: Valentin Lab <valentin.lab@kalysto.org>

src/install.sh

@@ -129,7 +129,7 @@ install_file() {
     cat > "${tmpfile}" || return 1
     mkdir -vp "${path%/*}" || exit 1
     if [[ -e "$path" ]]; then
-        if ! diff "${tmpfile}" "${path}";then
+        if ! diff "${tmpfile}" "${path}" >/dev/null 2>&1;then
             info "File '$path' exists but is different, archiving current content and replacing it."
             candidate="${path}.bak"
             n=1
@@ -189,7 +189,7 @@ fetch_binary() {
             echo "  .. ${RED}Failed${NORMAL} (fetched content is HTML !?!)." >&2
             return 1
         fi
-        if [ -e "$BIN_PATH/$name" ] && diff "$tmpfile" "$BIN_PATH/$name" >/dev/null; then
+        if [ -e "$BIN_PATH/$name" ] && diff "$tmpfile" "$BIN_PATH/$name" >/dev/null 2>&1; then
             echo "  .. ${GREEN}Done${NORMAL} (File '$BIN_PATH/$name' was already up to date.)" >&2
         else
             mv "$tmpfile" "$BIN_PATH/$name" &&