如何在行号处拆分 [英] How to file split at a line number

问题描述

我想从特定的行号中分割出一个40万行的日志文件.

I want to split a 400k line long log file from a particular line number.

对于这个问题，让我们将其设为任意数字300k.

For this question, lets make this an arbitrary number 300k.

是否存在允许我执行此操作的Linux命令(在脚本内)?

Is there a linux command that allows me to do this (within the script)?

我知道split让我按大小或行号将文件分成相等的部分，但这不是我想要的.我要在一个文件中的前300k，然后在第二个文件中的最后100k.

I know split lets me split the file in equal parts either by size or line numbers but that's not what I want. I want to the first 300k in one file and the last 100k in the second file.

任何帮助将不胜感激.谢谢！

Any help would be appreciated. Thanks!

再三考虑，这将更适合于超级用户或服务器故障站点.

推荐答案

file_name=test.log

# set first K lines:
K=1000

# line count (N): 
N=$(wc -l < $file_name)

# length of the bottom file:
L=$(( $N - $K ))

# create the top of file: 
head -n $K $file_name > top_$file_name

# create bottom of file: 
tail -n $L $file_name > bottom_$file_name

再考虑一下，拆分将在您的情况下起作用，因为第一次拆分大于第二次拆分.拆分将输入的余额放入最后的拆分中，因此

Also, on second thought, split will work in your case, since the first split is larger than the second. Split puts the balance of the input into the last split, so

split -l 300000 file_name

对于具有40万行的输入，将输出30万行的xaa和100k行的xab.

will output xaa with 300k lines and xab with 100k lines, for an input with 400k lines.

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