diff --git a/hls b/hls
index 1111993..bf6df66 100755
--- a/hls
+++ b/hls
@@ -21,11 +21,11 @@ help_text () {
 }
 
 download(){
-	printf "" > $failed
+	printf "" > "$failed"
 	for i in $1; do 
-	    curl --max-time 30 -s "${relative_url}$(printf "%s" "$data" | sed -n "${i}p")" > "$tmpdir/$(printf "%05d" "$i").ts" && printf "\033[2K\r\033[1;32m ✓ $i / $range done" || printf "$i\n" >> $failed &
+	    curl --max-time 30 -s "${relative_url}$(printf "%s" "$data" | sed -n "${i}p")" > "$tmpdir/$(printf "%05d" "$i").ts" && printf "\033[2K\r\033[1;32m ✓ %s / %s done" "$i" "$range" || printf "%s\n" "$i" >> "$failed" &
 	    jobs -p > "$jobdir"
-	    while [ "$(cat "$jobdir" | wc -l)" -ge $n ];do jobs > "$jobdir";sleep 0.05;done
+	    while [ "$(wc -l "$jobdir")" -ge "$n" ];do jobs > "$jobdir";sleep 0.05;done
 	done
 	wait
 }
@@ -43,7 +43,7 @@ while getopts 'o:rfhn:s:' OPT; do
                 f)	skip_ffmpeg=1;;
                 r)	skip_res=1;;
 		s)	subs=$OPTARG;;
-                *|h)
+                *)
                         help_text
                         exit 0
                         ;;
@@ -52,18 +52,18 @@ done
 shift $((OPTIND - 1))
 
 [ -z "$*" ] && printf "\033[1;34mEnter link >\033[0m " && read -r link || link=$* 
-trap "killall curl;rm -rdf $tmpdir $jobdir;exit 0" INT HUP
+trap "killall curl;rm -rdf '$tmpdir' '$jobdir';exit 0" INT HUP
 printf "\033[2K\r\033[1;36mFetching resolutions.."
 m3u8_data=$(curl -s "$link")
 res_list=$(printf "%s" "$m3u8_data" | sed -nE 's_.*RESOLUTION=.*x([^,]*).*_\1_p')
 if [ -n "$res_list" ];then
-        highest_res=$(printf "$res_list" | sort -nr | head -1)
-        [ -z "$skip_res" ] && printf "\033[2K\r\033[1;33mRESOLUTIONS >>\n\033[0m$res_list\n\033[1;34mType ur preferred resolution (default: $highest_res) > " && read -r sel_res || printf "\033[2K\r\033[1;36mSelecting highest resolution.."
+        highest_res=$(printf "%s" "$res_list" | sort -nr | head -1)
+        [ -z "$skip_res" ] && printf "\033[2K\r\033[1;33mRESOLUTIONS >>\n\033[0m%s\n\033[1;34mType ur preferred resolution (default: %s) > " "$res_list" "$highest_res" && read -r sel_res || printf "\033[2K\r\033[1;36mSelecting highest resolution.."
         [ -z "$sel_res" ] && sel_res=$highest_res
         unset highest_res res_list
         url=$(printf "%s" "$m3u8_data" | sed -n "/x$sel_res/{n;p;}" | tr -d '\r')
     #check whether the m3u8_data contains uri that starts from http
-        printf "%s" "$url" | grep -q "http" || relative_url=$(printf "%s" "$link" | sed 's_[^/]*$__')
+        printf "%s" "$url" | grep -q "http" || relative_url=$(printf "%s" "$link" | sed 's|[^/]*$||')
         printf "\033[2K\r\033[1;36mFetching Metadata.."
 	url="${relative_url}$url"
         resp="$(curl -s "$url")"
@@ -76,7 +76,7 @@ fi
 key_uri="$(printf "%s" "$resp" | sed -nE 's/^#EXT-X-KEY.*URI="([^"]*)"/\1/p')"
 [ -z "$key_uri" ] || iv_uri="$(printf "%s" "$resp" | sed -nE 's/^#EXT-X-IV.*URI="([^"]*)"/\1/p')"
 data="$(printf "%s" "$resp" | sed '/#/d')"
-printf "%s" "$data" | grep -q "http" && relative_url='' || relative_url=$(printf "%s" "$url" | sed 's_[^/]*$__')
+printf "%s" "$data" | grep -q "http" && relative_url='' || relative_url=$(printf "%s" "$url" | sed 's|[^/]*$||')
 range=$(printf "%s\n" "$data" | wc -l)
 
 #for encrypted stream only
@@ -87,14 +87,14 @@ if [ -n "$key_uri" ];then
 	[ -z "$iv_uri" ] && iv=$(openssl rand -hex 16) || iv=$(curl -s "$iv_uri" | od -A n -t x1 | tr -d ' |\n')
 fi
 
-printf "\033[2K\r\033[1;35mpieces : $range\n\033[1;33mDownloading.."
+printf "\033[2K\r\033[1;35mpieces : %s\n\033[1;33mDownloading.." "$range"
 #downloading .ts data asynchronously
 if command -v aria2c >>/dev/null;then
-	printf '%s' "$data" |  nl -n'rz' | sed -E "s|^([0-9]*)[[:space:]]*(.*)|${relative_url}\2\n\tout=\1.ts|g" | aria2c -x16 -s16 -j "$n" -d "$tmpdir" -i - --download-result=hide --summary-interval=0
+	printf '%s' "$data" |  nl -n'rz' | sed -E "s|^([0-9]*)[[:space:]]*(.*)|${relative_url}\2\n\tout=\1.ts|g" | aria2c -x16 -s16 -j "$n" -k'1M' -d "$tmpdir" -i - --download-result=hide --summary-interval=0 --allow-overwrite=true
 else
-	download "$(seq $range)"
+	download "$(seq "$range")"
 	#redownloading failed pieces
-	download "$(cat $failed)"
+	download "$(cat "$failed")"
 fi
 #downloading subtitles if uri passed using -s option
 [ -z "$subs" ] || curl -s "$subs" -o "$file.srt" &
@@ -107,17 +107,18 @@ if [ -n "$key_uri" ];then
 	openssl aes-128-cbc -d -K "$key" -iv "$iv" -nopad >> "$file.ts" < "$i"
     done
 else
-    printf "\033[2K\r\033[1;36m Concatenating pieces into single file.."
-    cat "$tmpdir"/* >> "$file.ts"
+    printf "\033[2K\r\033[1;36m Concatenating pieces into single file..\n"
+    cat "$tmpdir"/* | ffmpeg -loglevel error -stats -i - -c copy "$file.mp4" -y
+    skip_ffmpeg=1
 fi
 
-rm -rdf $tmpdir $jobdir $failed
+rm -rdf "$tmpdir" "$jobdir" "$failed"
 #conversion of allts file to mp4 video using ffmpeg..
 if [ -z "$skip_ffmpeg" ];then
     printf "\033[2K\r\033[1;36mEncoding file to mp4 video..\n\033[0m"
     ffmpeg -i "$file.ts" -loglevel error -stats -c copy "$file.mp4"
 else
-    mv "$file.ts" "$file.mp4"
+    [ -f "$file.ts" ] && mv "$file.ts" "$file.mp4"
 fi
 
 #cleanup..