enhance_daily_log_clean.sh

#!/bin/bash

LOG_USER_DIR="/var/www"
LOG_SERVER_DIR="/var/log"
TRUNC_USER_SIZE="+3M"
TRUNC_USER_BYTES=3145728
TRUNC_SERVER_SIZE="+50M"
TRUNC_SERVER_BYTES=52428800
JOURNAL_RETENTION_DAYS=10
POSTFIX_LOG="/var/log/postfix.log"

truncate_logs() {
  local dir=$1
  local size_filter=$2
  local label=$3
  local bytes files file temp_file

  printf "=== [%s] Scanning %s for files > %s ===\n" "$label" "$dir" "$size_filter"

  if [[ "$label" == "User Logs" ]]; then
    bytes=$TRUNC_USER_BYTES
    files=$(find "$dir" \
      -path "*/cpf_logs/*" -prune -o \
      \( -name "*.log" -o -name "*_log" \) -type f -size "$size_filter" -print 2>/dev/null)
  else
    bytes=$TRUNC_SERVER_BYTES
    files=$(find "$dir" \( -name "*.log" -o -name "*_log" \) -type f -size "$size_filter" 2>/dev/null)
  fi

  if [[ -z "$files" ]]; then
    printf "[%s] No files to process.\n\n" "$label"
    return
  fi

  while IFS= read -r file; do
    printf "[%s] Processing: %s\n" "$label" "$file"

    if [[ ! -f "$file" || ! -r "$file" || ! -w "$file" ]]; then
      printf "[%s] Skipping inaccessible file: %s\n" "$label" "$file"
      continue
    fi

    if [[ "$file" == "$POSTFIX_LOG" ]]; then
      printf "[%s] Clearing postfix log: %s\n" "$label" "$file"
      if : > "$file"; then
        printf "[%s] Successfully cleared postfix log\n" "$label"
      else
        printf "[%s] ERROR clearing postfix log\n" "$label"
      fi
      continue
    fi

    temp_file=$(mktemp) || {
      printf "[%s] ERROR creating temporary file\n" "$label"
      continue
    }

    printf "[%s] Truncating to last %d bytes\n" "$label" "$bytes"
    if tail -c "$bytes" "$file" > "$temp_file" && cp "$temp_file" "$file"; then
      printf "[%s] Successfully truncated: %s\n" "$label" "$file"
    else
      printf "[%s] ERROR truncating %s\n" "$label" "$file"
    fi

    rm -f "$temp_file"
  done <<< "$files"

  printf "[%s] Done.\n\n" "$label"
}

clean_journal() {
  printf "=== [Journal] Vacuuming logs older than %sd ===\n" "$JOURNAL_RETENTION_DAYS"
  if sudo journalctl --vacuum-time="${JOURNAL_RETENTION_DAYS}d" > /dev/null 2>&1; then
    printf "[Journal] Vacuum completed successfully.\n\n"
  else
    printf "[Journal] ERROR during vacuum operation.\n\n"
  fi
}

main() {
  printf ">>> Starting log maintenance at %s <<<\n\n" "$(date '+%Y-%m-%d %H:%M:%S')"

  truncate_logs "$LOG_USER_DIR" "$TRUNC_USER_SIZE" "User Logs"
  truncate_logs "$LOG_SERVER_DIR" "$TRUNC_SERVER_SIZE" "Server Logs"
  clean_journal

  printf ">>> Finished at %s <<<\n" "$(date '+%Y-%m-%d %H:%M:%S')"
}

main