shell - 如何使用“拆分”命令

Question

我有一个包含 2000 行的文件。我使用以下内容每 100 行拆分文件。

split -l 100 file.txt outputfile.txt

我想在每个文件内容的末尾添加一个“FFFFFF”，在拆分之后我还想指定文件使用的扩展名，就像上面的命令一样，输出如下。

outputfile.txtxa, outputfile.txtxb etc...

我已经阅读了拆分的手册页并浏览了网页，但是我找不到解决方案。

任何建议表示赞赏。

Answer 1

For a one pass solution, you could use awk like this:

awk 'NR%100==1 { ++i } { print $0 (NR%100==0 ? "\nFFFFFF" : "") > "outputfile" i ".txt" }' file.txt

Also, the advantage here is finer control over the output filenames to make them more pretty. Please let me know if you require something more fancy. Cheers.

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Explanation for user1937:

If you are familiar with the modulo operator, NR%100==1 will return true for the 1st line, the 101st line, the 201st line, the 301st line etc. Each time it's true, the variable i is incremented. Notice how an awk statement is made up of condition/action blocks. So NR%100==1 is the condition and ++i is the action. What you'll then notice (hopefully) is that the block that has the print action lacks a conditional. Therefore every line of input is being printed (all of the time). The value of i simply determines which file the output is being printed to.

Another bit you may not be familiar with is: (NR%100==0 ? "\nFFFFFF" : ""). This is a ternary operator which is shorthand for: if (NR%100==0) print "\nFFFFFF"; else print ""). HTH.

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awk code can be built using pattern/action statements in the form:

NR%100==1                             # pattern1
{
    ++i                               # action1
}

{
    print $0 ...                      # action2
}

As you can see, pattern1 only applies to action1. pattern1 does not apply to action2.

Answer 2

你不能单独使用 split 来做到这一点。此代码可能会有所帮助：

split -l 100 file.txt outputfile_
find . -name outputfile_\* -exec sh -c 'echo "FFFFFF" >> {} && mv {} {}.txt' \;

这将导致文件outputfile_aa.txt等outputfileab.txt，它们都将以FFFFFF.

其工作原理如下：首先我们使用前缀拆分文件outputfile_以生成文件outputfile_aa等outputfile_ab。然后我们调用find命令将它们全部收集起来并使用它执行命令。有一个小问题是你不能在 find 命令中使用重定向，所以我们将把重定向包装到一个 shell 脚本中并使用sh. 将{}被每个单独的文件名替换（-exec在find的手册页中查找）；因此，脚本将首先将FFFFFF字符串附加到文件的末尾，然后重命名文件以添加txt扩展名。