cat /sys/block/sdX/queue/rotational

# or

apt install util-linux
lsblk -d -o name,rota # 1=HDD, 0=SSD

grep --color=always -rin term . | less -R

# single file
rrdtool dump    infile.rrd outfile.xml
rrdtool restore infile.xml outfile.rrd

# massive
for i in *.rrd; do rrdtool dump    $i ${i%.rrd}.xml; done
for i in *.xml; do rrdtool restore $i ${i%.xml}.rrd; done

rsync -v -s -P -e ssh \
  username@remote_host:/path/to/remote_file.ext \
  local_file.ext

rsync --verbose \
  --protect-args \
  --partial --progress \
  --rsh=ssh \
  username@remote_host:/path/to/remote_file.ext \
  local_file.ext