Shell脚本实现为.lvm文件指定行列写入标识值的问题求助

Hey there! Let's get your scripts sorted to produce that desired output. I'll walk through fixing each script step by step, since your current code has a few syntax issues and missing logic.

First Script: Process .lvm Files & Add End-of-File Marker #

Your first script needs to: skip the file header (up to the X_Value line), add the filename as the first column, set column 18 (now column 19 after adding the filename) to 0 for all lines except the last one, which gets 500. Here's the corrected version:

#!/bin/sh

# Iterate over all .lvm files in the directory passed as argument
for file in "$1/"*.lvm; do
    # Extract just the filename (without the full path)
    filename=$(basename "$file")
    # Find the line number where "X_Value" appears (end of header)
    header_line=$(awk '/X_Value/{ print NR; exit }' "$file")
    # Calculate the first line of actual data (right after the header)
    start_line=$((header_line + 1))

    # Use awk to process the file:
    # 1. Skip header lines before start_line
    # 2. Prepend the filename as the first column
    # 3. Set the appropriate value for the marker column (originally column 18, now 19)
    awk -v start="$start_line" -v fname="$filename" '
        BEGIN {OFS = "\t"}  # Set output field separator to tab
        NR < start {next}   # Skip all header lines
        {
            # Add filename as the first field
            $0 = fname "\t" $0
            # Check if this is the last line of the file
            if (NR != END) {
                $(19) = 0  # Non-last lines get 0 in the marker column
            } else {
                $(19) = 500  # Last line gets 500
            }
            print $0
        }
    ' "$file"
done

Key fixes here:

• Removed the unnecessary clear command and fixed syntax issues
• Properly extracts the filename to prepend to each line
• Correctly skips header lines using the X_Value marker
• Adjusted the target column to 19 (since we added a new first column for the filename)
• Uses valid awk logic to set the marker value based on whether the line is the last one in the file

Second Script: Extract Desired Columns #

Your second script needs to output the 5 original columns plus the new marker column. Since we added the filename as column 1, the original columns shift right by 1. Here's the updated script:

#!/bin/sh

# Read input line by line, extract desired columns including the marker
while read -r line; do
    awk -v OFS='\t' '{print $1, $2, $3, $8, $18, $19}' <<< "$line"
    sleep 1  # Keep your sleep if you need it for pacing/output
done

# Alternatively, for better performance (skip the while loop):
# awk -v OFS='\t' '{print $1, $2, $3, $8, $18, $19}'

How to Run #

Just use your existing pipeline setup:

./first_script.sh /path/to/your/lvm/files | ./second_script.sh

This will produce output matching your desired format, with each file's lines ending in 0 except the final line which ends in 500.

内容的提问来源于stack exchange，提问作者Jovel