linux command to hanlde big file eg use ncdu

viewbigfile() {
  # ref https://www.plesk.com/kb/support/how-to-find-directories-files-that-take-up-the-most-disk-space-on-a-plesk-for-linux-server/

  find / -type f -size +200M             -exec du -h {} + 2>/dev/null | sort -r -h
  #    /               +200M <- find it
}

reduce_journal_log() {
  # ref https://www.sitelint.com/blog/how-do-i-clear-a-big-var-log-journal-folder#:~:text=You%20can%20safely%20clean%20%2Fvar,cannot%20delete%20the%20directory%20itself.
  sudo journalctl --vacuum-size=100M
}

# ncdu to view what occupied big size  ref https://askubuntu.com/a/57760/22308
apt-get install ncdu

clenup_tmp_safely() {
  # ref https://superuser.com/a/499053/34893
  find /tmp -mtime +1     -and -not -exec fuser -s {} ';'       -and -exec rm {} ';'
  #                +1 day           -exec fuser -s {} ';' the unaccessed one
}

# maybe tmpreaper also helpful  ref https://superuser.com/a/839408/34893
tmpreaper 1d    /tmp
#         1day  folder to reap