file | psylogical.org

Check .deb package files

Install required packages
apt install apt-file
apt-file update apt-file list package_name

File size

Use this when looking for rapidly growing file sizes

Show files bigger that 100MB
find . -size +100000k

Show biggest files per directory
du -sm * | sort -nr | head

Send file from cmd line

This way you send file directly from command line
echo "body" | mutt -a "/path/to/file" -s "subject" -- name@hostname