Only default to empty string when variables are unset

downloadPOSIX.sh

@@ -21,9 +21,9 @@ IFS="
 POSIXLY_CORRECT='1'
 COMMANDS_='builtin unalias unset read printf command exit type . tr mkdir wc sed grep xargs ffmpeg jq wget'
 # shellcheck disable=SC2086
-\unset -f -- ${COMMANDS_:-} 2>/dev/null
+\unset -f -- ${COMMANDS_-} 2>/dev/null
 # shellcheck disable=SC2086
-\unalias -- ${COMMANDS_:-} 2>/dev/null || true
+\unalias -- ${COMMANDS_-} 2>/dev/null || true
 
 command -v -- wget >/dev/null 2>&1 || {
     printf '\033[31m%s\033[m\n' "Please install wget"
@@ -79,11 +79,11 @@ api-version=1.4-private
 EOM
 
 API_URL="$(
-    printf '%s' "${API_URL:-}" |
+    printf '%s' "${API_URL-}" |
     tr -d -- '\t'
 )"
 
-mkdir -p -- "${OUTDIR:-}" || {
+mkdir -p -- "${OUTDIR-}" || {
     printf '\033[31m%s\033[m\n' 'Aborting'
     exit 2
 }
@@ -95,44 +95,44 @@ m3u8_manifest_urls_and_metadata="$(
     wget --no-verbose                                               \
         --quiet                                                     \
         --output-document -                                         \
-        --header="authorization: Bearer ${BASE64_BEARER_TOKEN:-}"     \
-        -- "${API_URL:-}"                                             |
+        --header="authorization: Bearer ${BASE64_BEARER_TOKEN-}"     \
+        -- "${API_URL-}"                                             |
         jq --raw-output                                             \
         '.value[] | .name + ">" + .media.duration[2:] + ">" + (.playbackUrls | map(select(.mimeType == "application/vnd.apple.mpegurl")) | .[].playbackUrl)'
 )"
 
-[ -z "${m3u8_manifest_urls_and_metadata:-}" ] && {
+[ -z "${m3u8_manifest_urls_and_metadata-}" ] && {
     printf '\033[31m%s\033[m\n' 'Error GETting manifest urls (response empty) or Bearer token invalid/expired. Exiting.'
     exit 3
 }
 
 idx='1'
-total="$(printf '%s\n' "${m3u8_manifest_urls_and_metadata:-}" | wc -l)"
+total="$(printf '%s\n' "${m3u8_manifest_urls_and_metadata-}" | wc -l)"
 
 IFS='
 '
-for m3u8_manifest_url_and_metadata in ${m3u8_manifest_urls_and_metadata:-}
+for m3u8_manifest_url_and_metadata in ${m3u8_manifest_urls_and_metadata-}
 do
     IFS='>' read -r title length m3u8_manifest_url <<- EOM
-				${m3u8_manifest_url_and_metadata:-}
+				${m3u8_manifest_url_and_metadata-}
 		EOM
 
-    length="$(printf '%s' "${length:-}" | sed -e 's/\..*S/S/g' -e 's/M/:/g' -e 's/H/:/g')"
+    length="$(printf '%s' "${length-}" | sed -e 's/\..*S/S/g' -e 's/M/:/g' -e 's/H/:/g')"
 
-    filepath="${OUTDIR:-}/${title:-}.mp4"
+    filepath="${OUTDIR-}/${title-}.mp4"
 
-    printf '\033[32m%s\033[m\n' "Download '${filepath:-}' (${idx:-}/${total:-})"
+    printf '\033[32m%s\033[m\n' "Download '${filepath-}' (${idx-}/${total-})"
 
     ffmpeg -hide_banner                                                \
         -loglevel error                                                \
-        -headers "authorization: Bearer ${BASE64_BEARER_TOKEN:-}"        \
-        -i "${m3u8_manifest_url:-}"                                      \
+        -headers "authorization: Bearer ${BASE64_BEARER_TOKEN-}"        \
+        -i "${m3u8_manifest_url-}"                                      \
         -progress -                                                    \
         -c copy                                                        \
-        "${filepath:-}"                                                  |
+        "${filepath-}"                                                  |
             grep --line-buffered 'out_time='                           |
             sed -u -e 's/out_time=//g' -e 's/\..*//g' -e 's/^-//g'     |
-            xargs -I{} printf '%s\r' "{} of ${length:-}       "
+            xargs -I{} printf '%s\r' "{} of ${length-}       "
 
     printf '\n\033[33m%s\033[m\n' "Done"