Handy commands

# Convert m4a to mp3
ffmpeg -i audioFile.m4a -codec:v copy -codec:a libmp3lame -q:a 2 audioFile.m4a.mp3

# Download extracted audio content from youtube video
youtube-dl -x "Youtube-link"

# Find and replace "Oldcontent" to "Newcontent" in FILENAME
sed -i.bak s%Oldcontent%Newcontent%g FILENAME

# Replace a word with another in all file under a directory structure
find ./ -type f -exec sed -i s%Oldcontent%Newcontent% {} +

# Replace part of the directory and filenames on all files and directory under a directory
find . -depth -name '*Oldnamepart*' -execdir bash -c 'for f; do mv -i "$f" "${f//Oldnamepart/Newnamepart}"; done' bash {} +

# Find the last modified file under a directory structure
find . -type f -printf '%T@ %p\n' | sort -n | tail -1 | cut -f2- -d" "