[Ubuntu] Convert mp4 video to aac audio

 

#!/bin/bash

# Define the target directory
directory="."

# Check if the target is not a directory
if [ ! -d "$directory" ]; then
  exit 1
fi

# Loop through files in the target directory
for file in "$directory"/*; do
  if [ -f "$file" ]; then
    if [ "${file##*.}" == "mp4" ]; then
        echo "${file%.*}.aac"
        ffmpeg -i "$file" -c:a aac -b:a 128k -vn "${file%.*}.aac"
    fi
  fi
done

 

[Ubuntu] find command with grep

 find -name "*.java" -exec grep "foo" -Hn {} \;

 

-H Display filesname

-n Display line number

[Ubuntu] Create tar file exclude specified directory

Tar foo directory, and exclude "foo/.repo"  directory

─foo

   ├─.repo

   │     └─ example

   └─ 1.txt

$ tar -cvf foo.tar --exclude='foo/.repo' foo

Remove directory "foo/.repo" from tar file

$ tar --delete foo/.repo -f foo.tar

[Ubuntu] Split large file into smaller pieces

Split file into per file 1024MB

split -b 1024M -d foo.tar.xz foo.tar.xz-

foo.tar.xz-00    1024MB

foo.tar.xz-01    1024MB

...

Merge pieces to large file

cat foo.tar.xz-* > foo.tar.xz

[Mac OS] React Native - Environment Setting

 Trouble Shooting:

% bundle install

Your Ruby version is 2.6.3, but your Gemfile specified 2.7.4

or 

Your Ruby version is 2.6.8, but your Gemfile specified 2.7.5

[Firefox] Youtube video decoding with hardware acceleration (GPU)

 Windows下使用Firefox看Youtube影片時，用工作管理員觀察，發現GPU的使用率都為0，但如果用Chrome則會使用到GPU。最後發現以about:config進行修改，就可以讓Firefox使用GPU 加速影片decoding。

[7zip] 壓縮及分割檔案

壓縮比例

-mx=5

可填入數值0(封存),1,3,5(預設),7,9(最大壓縮比)

壓縮檔案分割大小

-v650m

可填入單位b(bytes),k(KB),m(MB),g(GB)

範例:

封存Source目錄，以650MB分割壓縮檔，以aaa.7z為壓縮檔名

 7z a -mx=0 -v650m aaa.7z Source