AWK能否比Bash循环更快地转置指定格式的数据？

Here's an efficient AWK script that processes your data in a single pass, eliminating the need for multiple grep/cut calls in loops:

BEGIN {
    FS = ","
    # Define the desired column order for output
    cols[1] = "LAST_VULN_AGENT_SCAN"
    cols[2] = "LAST_VULN_NONCRED_SCAN"
    cols[3] = "LAST_VULN_CRED_SCAN"
}

{
    target = $1
    scan_type = $2
    timestamp = $3
    # Store timestamp mapped to target and scan type
    data[target][scan_type] = timestamp
    # Track unique targets to maintain order
    if (!(target in targets)) {
        targets[target] = 1
        target_list[++num_targets] = target
    }
}

END {
    # Print header row
    printf "Name"
    for (i = 1; i <= 3; i++) {
        printf ",%s", cols[i]
    }
    printf "\n"
    
    # Print each target's consolidated row
    for (i = 1; i <= num_targets; i++) {
        current_target = target_list[i]
        printf "%s", current_target
        for (j = 1; j <= 3; j++) {
            printf ",%s", data[current_target][cols[j]]
        }
        printf "\n"
    }
}

How to Use #

Run it with your existing DATA variable like this:

echo "$DATA" | awk -f script.awk

Or use the inline version if you prefer:

echo "$DATA" | awk 'BEGIN {FS=","; cols[1]="LAST_VULN_AGENT_SCAN"; cols[2]="LAST_VULN_NONCRED_SCAN"; cols[3]="LAST_VULN_CRED_SCAN"} {target=$1; scan_type=$2; timestamp=$3; data[target][scan_type]=timestamp; if(!(target in targets)) {targets[target]=1; target_list[++num_targets]=target}} END {printf "Name"; for(i=1;i<=3;i++) printf ",%s", cols[i]; print ""; for(i=1;i<=num_targets;i++) {current_target=target_list[i]; printf "%s", current_target; for(j=1;j<=3;j++) printf ",%s", data[current_target][cols[j]]; print ""}}'

Key Advantages Over Bash Loop #

• Single Pass Processing: The AWK script reads your data once instead of reprocessing it for every target and scan type, drastically improving performance with large datasets.
• Cleaner Logic: Uses associative arrays to map targets to their scan timestamps, avoiding messy nested grep/cut commands.
• Maintains Order: Preserves the order of targets as they first appear in the input (you can sort target_list in the END block if you need alphabetical order).

内容的提问来源于stack exchange，提问作者27560