Differences

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--- quick_command_list [2018/05/22 17:59] – [Ping packet size] k2patel
+++ quick_command_list [2022/05/16 20:05] (current) – [remove comments and blank lines from output] k2patel
@@ Line 333: / Line 333: @@
 grep -v -e '^#\|^\W*$'
 </code>
+OR
+<code bash>
+grep '^[[:blank:]]*[^[:blank:]#;]' $file
+</code>
 ==== Calculating Date ====
@@ Line 457: / Line 460: @@
 :!: Regex can be modified to list all matching file before removal.
+==== Testing connection or port without any software ====
+In linux proper way to test tcp or udp port connection without any software installed should be creating dev node.
+<code bash>
+/dev/<proto>/<host>/<port>
+</code>
+out put can be redirected to tty with help of cat.
+<code bash>
+cat < /dev/tcp/k2patel.in/3306
+</code>
+==== Setting id tag on mp3 ====
+Setting mp3 tag on multiple file based on filename as song name.\\
+Same artist.
+<code bash>
+while read k2; do id3tag -a'xyz guru' -A'SuperSpeed' -s"${k2%%.*}" -y'2021' "${k2}" ; done < <(ls *.mp3)
+</code>
+==== FFMpeg Conversion of 4K ====
+I had issue of no audio while playing file over DLNA.\\
+I've did the transcoding so it can play audio on my Phillips 4K TV.
+<code bash>
+ffmpeg -i <input_file>.mp4  \
+    -map 0:0 -map 0:1 -map 0:2 -map 0:3 -map 0:5 -map 0:12 \
+	-c:v copy \
+	-c:a:0 truehd -strict -2 \
+	-c:a:1 ac3 \
+	-c:s copy \
+	<output_file>.mkv
+</code>
+OR
+<code bash>
+ffmpeg -i old_file.mp4 \
+    -map 0:0 -map 0:1 -map 0:3 -map 0:5 \
+    -c:v copy \
+    -c:a:0 ac3 \
+    -c:s copy \
+    new_file.mp4
+</code>
+OR
+<code bash>
+ffmpeg -i old_file.mkv \
+    -map 0:0 -map 0:1 -map 0:2 \
+    -c:v copy \
+    -c:a:0 ac3 \
+    -c:s copy \
+    -disposition:s:0 forced \
+    new_file.mkv
+</code>
+  - First thing list all mapping on your existing file using 'ffmpeg -i <file>
+  - Select all streams using map you would like to copy to your new file.
+  - each map should be listed using map so i selected only 6 out of 12.
+  - After that specify wich codecs to use.
+  - in -c:v i'm copying video as is.
+  - in -c:a:0 i'm converting audio to truehd
+  - in -c:a:1 i'm also adding second audio stream which is ac3.
+  - in -c:s i'm copying subtitles.