Prune oldest of files matching a "find" name pattern leaving NUM_KEEP on disk (useful for deleting old backups)

prune-old

#!/bin/bash

#
# Note: Ignores files with ".part" suffix
#


NUM_KEEP=5

# example invocation: /usr/local/bin/prune-old /backup "gitlab-embedded-db*.dump"
#
function usage() {
  echo "Usage: $0 'dir' 'pattern'" >&2
}

(($# < 2)) && {
  echo "Error in invocation" >&2
  usage
  exit 1
}

dir="$1"; shift
pattern="$1"; shift


declare -a files
files=( $(find "$dir" -name "$pattern" -type f -and -not -name "*.part" -printf "%T@ %Tc %p\n" | sort -n | awk '{print $NF}') )

echo "Total files to consider for pruning given pattern \"$pattern\" (${#files[@]}): ${files[@]}" >&2

ex=0

((${#files[@]} > NUM_KEEP)) && {
  ct=0
  for file in "${files[@]}"; do
    ((ct == ${#files[@]}-NUM_KEEP)) && {
      echo "Deleted enough old files ($ct), leaving the rest ($NUM_KEEP)" >&2
      break
    }

    echo "++ Deleting $file"
    rm -f "$file" || {
      ex=4
      break
    }
    ct=$((ct+1))
  done
}


((ex > 0)) && {
  echo -e "\nError occured" >&2
}

echo "Exiting."
exit $ex