如何按首列的6和7值拆分制表符分隔文本文件的记录？

Here are two practical, efficient ways to split your tab-delimited file into separate output files, where each file contains records starting with a line beginning with 6 and ending with the next line starting with 7:

Solution 1: Using Awk (Recommended) #

Awk is purpose-built for this kind of text processing. This one-liner will handle the split seamlessly:

awk '/^6/{f="file"++n".txt"} f{print > f; if(/^7/) close(f)}' your_input_file.txt

How it works: #

• /^6/{f="file"++n".txt"}: When a line starts with 6, we create a new output file name (e.g., file1.txt, file2.txt) by incrementing a counter each time a new block starts.
• f{print > f; if(/^7/) close(f)}:
  • If we have an active output file (we’ve already found a starting 6 line), write the current line to that file.
  • When we hit a line starting with 7, close the file to avoid hitting system limits on open files (critical if you have many blocks).

Solution 2: Using a Bash Script (For Explicit Control) #

If you prefer a more verbose, customizable approach, here’s a bash script that achieves the same result:

#!/bin/bash
input_file="your_input_file.txt"
file_counter=1
active_output=""

while IFS= read -r line; do
    # Start a new file when we hit a line starting with 6
    if [[ "$line" =~ ^6 ]]; then
        active_output="file${file_counter}.txt"
        echo "$line" > "$active_output"
    # Append to the active file if it exists
    elif [[ -n "$active_output" ]]; then
        echo "$line" >> "$active_output"
        # Close the file and increment counter when we hit a line starting with 7
        if [[ "$line" =~ ^7 ]]; then
            file_counter=$((file_counter + 1))
            active_output=""
        fi
    fi
done < "$input_file"

How it works: #

• We initialize a counter for output files and a variable to track the current active file.
• For each line in the input:
  • If it starts with 6, we create a new output file and write the line to it.
  • If we have an active output file, append the line to it. When we hit a line starting with 7, we increment the counter and reset the active file variable.

Verification #

After running either method, you can verify the output by checking files like file1.txt—it should contain the first block of lines from your input, starting with 6 and ending with 7.

内容的提问来源于stack exchange，提问作者Bihag