improve comments

mythtv/channel_sort_mythtv.sh

@@ -37,14 +37,16 @@
 
 set -eu
 
+# you can override the mysql.txt location by providing it via an environment variable
 MYSQL_CONF_FILE=${MYSQL_CONF_FILE:-}
 
 # only used for "set" operation:
 # 	use this channel number for all channels, that are listed in stdin
-#	set to an empty string, if the channels, that are not listed, should remain untouched
+#	set it to an empty string, if the channels, that are not listed, should remain untouched
 DEFAULT_CHANNEL=10000
 
 # set DEBUG to a non-empty string to output the result sql statements instead of executing them
+# use something like "export DEBUG=true" before running this script to enable debug mode
 DEBUG=${DEBUG:-false}
 export DEBUG
 
@@ -56,6 +58,7 @@ for mysql_config in "$MYSQL_CONF_FILE" ~/.mythtv/mysql.txt /etc/mythtv/mysql.txt
 		break
 	 fi
  done
+# temporarily disable the "unset variable check" of bash
 set +u
 if test -z "$DBHostName" -o -z "$DBUserName" -o -z "$DBName" -o -z "$DBPassword"; then
 	echo "Failed to read the mysql settings file of MythTV." >&2
@@ -66,7 +69,7 @@ set -u
 
 send_mysql_statement() {
 	if test "$DEBUG" != "false"; then
-		# show a blank first line, since it would get removed in "get" otherwise
+		# only output the sql statements - don't execute them
 		cat -
 	 else
 		mysql -h "$DBHostName" -u "$DBUserName" --password="$DBPassword" --skip-column-names "$DBName"
@@ -108,7 +111,6 @@ case "$ACTION" in
 				current_num=$((current_num + 1))
 			 done
 		) | send_mysql_statement
-		
 		;;
 	merge)
 		input="$(cat -)"