The issue addressed is when is required to test if file is empty. But before that is needed to check if the file exist, I tried this and it worked.
[ -f /etc/hosts ] && echo "Found" || echo "Not found"
2.- Variable empty
Check if a variable is empty before to check if the file path in the variable exist.
if [ -z "$var" ]
echo "\$var is empty"
echo "\$var is NOT empty"
3.- Convert from ogg to mp3
ffmpeg -i audio.ogg -acodec libmp3lame audio.mp3
And also the script.
4. Process a list of files
In this link is showed how
for i in *.txt
5. Execute scripts remotely using a local script
ssh email@example.com < ./src/main/resouces/shell_scripts/unix_code.sh
check this link for more details