( Fisher | 2024. 05. 29., sze – 11:29 )

Érdekességképp itt van, amit nekem dobott, és ez tetszik is, alighanem erre megyek majd:

You can replace the loop with a single awk command to streamline the process. Here is an approach to achieve that:

1. Read the HostName values into an array.
2. Use awk to process the CACHEFILE for all hostnames at once.
3. Use awk to generate the SQL update statements.

Here's how you can do it:

awk -v CACHEFILE="${CACHEFILE}" '
  BEGIN {
    # Load hostnames into an array
    while ((getline hostname < "hostnames.txt") > 0) {
      hostnames[hostname]
    }
    close("hostnames.txt")
  }
  {
    # Process each line of CACHEFILE
    if ($NF in hostnames) {
      if ($1 > timestamps[$NF]) {
        timestamps[$NF] = $1
      }
    }
  }
  END {
    for (hostname in timestamps) {
      if (timestamps[hostname] > 0) {
        printf "UPDATE servers set backup=\"%s\" WHERE hostname=\"%s\";\n", timestamps[hostname], hostname >> "'${SQLFILE}'"
      }
    }
  }
' "${CACHEFILE}"

Explanation:

1. BEGIN Block:

   • Read the hostnames from a file (hostnames.txt), where each line contains a HostName. Store these hostnames in an array.

2. Main Block:

   • For each line of the CACHEFILE, check if the last field ($NF) is in the array of hostnames.
   • If it is, and if the first field ($1) is greater than the current maximum timestamp for that hostname, update the timestamp for that hostname.

3. END Block:

   • For each hostname, if there is a valid timestamp, print the SQL update statement to the SQLFILE.

Replace "hostnames.txt" with the path to your file containing the list of hostnames. This approach ensures that you process all hostnames and generate the SQL update statements in one go, avoiding the need for a loop.