scp-delete-during-transfer.sh: for when you're running out of disk space and need to scp a file out while deleting chunks of it

scp-delete-during-transfer.sh

#! /usr/bin/env -S bash -e

SSH_USERHOST="user@host"
REMOTE_PATH="/tmp/disk_backup.img"

OUT_PATH="./$(basename ${REMOTE_PATH})"
TMP_PATH="/tmp/ssh-big-copy"
SLICES=200

echo -e "\nGetting from ${SSH_USERHOST}: ${REMOTE_PATH}\n"

TOT_SZ=$(ssh ${SSH_USERHOST} "du -b ${REMOTE_PATH}" | egrep -o '^[0-9]+')
SLICE_SZ_M=$((TOT_SZ/SLICES/1024/1024+1))

echo -e "Total size: ~$((TOT_SZ/1024/1024))M"
echo -e "Per slice: ~${SLICE_SZ_M}M (${SLICES} slices)"

mkdir "${TMP_PATH}"

for i in $(seq -w 1 ${SLICES} | sort -nr); do
    echo -e "\nGetting slice with findex ${i} ...\n"

    TO_SKIP_B=$((TOT_SZ-(SLICE_SZ_M*1024*1024)))
    if [ ${TO_SKIP_B} -lt 0 ]; then TO_SKIP_B=0; fi

    ssh "${SSH_USERHOST}" "dd if=\"${REMOTE_PATH}\" bs=1M iflag=skip_bytes skip=${TO_SKIP_B} count=${SLICE_SZ_M}" > "/tmp/ssh_out.tmp.${i}"

    ssh "${SSH_USERHOST}" "truncate -s \"${TO_SKIP_B}\" \"${REMOTE_PATH}\""
    TOT_SZ=${TO_SKIP_B}
    echo -e "Remaining size = ${TOT_SZ}\n"
done

echo -en "Writing ... "
cat /tmp/ssh_out.tmp.* > "${OUT_PATH}"
md5sum "${OUT_PATH}"

echo -e "\nCleaning up ..."
rm -r "${TMP_PATH}"