Change from backticks to $() as command substitution

Author: rodrigocnascimento

scripts/network_bandwith.sh

@@ -7,16 +7,16 @@ network_name=$(tmux show-option -gqv "@dracula-network-bandwith")
 main() {
   while true
     do
-      initial_download=`cat /sys/class/net/$network_name/statistics/rx_bytes`
-      initial_upload=`cat /sys/class/net/$network_name/statistics/tx_bytes`
+      initial_download=$(cat /sys/class/net/$network_name/statistics/rx_bytes)
+      initial_upload=$(cat /sys/class/net/$network_name/statistics/tx_bytes)
 
       sleep $INTERVAL
 
-      final_download=`cat /sys/class/net/$network_name/statistics/rx_bytes`
-      final_upload=`cat /sys/class/net/$network_name/statistics/tx_bytes`
+      final_download=$(cat /sys/class/net/$network_name/statistics/rx_bytes)
+      final_upload=$(cat /sys/class/net/$network_name/statistics/tx_bytes)
 
-      total_download_bps=`expr $final_download - $initial_download`
-      total_upload_bps=`expr $final_upload - $initial_upload`
+      total_download_bps=$(expr $final_download - $initial_download)
+      total_upload_bps=$(expr $final_upload - $initial_upload)
 
       total_download_kbps=$(echo "scale=2; $total_download_bps / 1024" | bc)
       total_upload_kbps=$(echo "scale=2; $total_upload_bps / 1024" | bc)