外观
manipulate disk partition table. fisk -l
report file system disk space usage. df -h
du -ahx / | sort -rh | head -n 20 #-a:包含文件和目录 #-h:以人类可读格式(KB/MB/GB)显示 #-x:只在本文件系统内查找(不跨挂载点)
convert and copy a file