Question

我有一个包含大量文件的文件夹。在其中一些文件中有一行像这样

id = "8c09e1ce-56b6-4aa5-8307-8998f507b594"

所有这些id都是唯一的。

我想编写一个命令，为所有id s

生成新的唯一值

我有sed命令与原始行's/id = \"[a-zA-Z0-9-]\{36\}\"//g'匹配，但我不知道如何动态地让替换工作。

有一些类似的StackOverflow问题（like this one），但我无法使解决方案在OSX和Linux上可靠地工作，这是我的要求之一。他们都安装了uuidgen。

显然，首选简洁易读的东西。

Answer 1

For in-placing editing with sed's -i option, there is no cross-platform syntax that works without creating a backup file, as explained in this answer of mine (you must use either -i '' (BSD/macOS) or just -i (GNU), but with creation of a backup file something like -i.bak does work with both implementations).

That said, awk is the better tool for this task anyway, because Awk scripts allow invoking shell commands and external utilities on demand:

find . -type f -name '*.extension' | while IFS= read -r fpath; do
  awk '
    BEGIN { FS=OFS=" = " } 
    $2 ~ /^\"[a-zA-Z0-9-]+\"$/ { "uuidgen" | getline uuid; $2 = "\"" uuid "\"" }
    1
  ' "$fpath" > "$fpath.tmp" && mv "$fpath.tmp" "$fpath"
done

^{This assumes that filenames have no embedded newlines, which is rarely a real-world concern.}

The command uses only POSIX-compliant shell features, utilities and options, with the exception of:
- the uuidgen utility, which, however, is available on both Linux and macOS, as well as FreeBSD and its variants.
Sadly, Mawk (which is Ubuntu's default Awk) doesn't support duplication expressions such as {36}, which is why the less specific + is used above; if you know that you'll be using only either BSD or GNU Awk, however, you can still use {36}.
The command supports replacing multiple UUIDs in each input file.

On a side note: GNU Awk v4.1+ allows in-place updating with -i inplace, similar to Sed's -i option, which would allow for a single-command find solution with -exec, but neither BSD Awk nor Mawk support it.

Answer 2

所以我想通了（作弊）。

每个文件只有一个id所以我决定迭代文件并分别为每个文件运行sed，如下所示：

for i in `find . -name "*.extension" -type f`; do
    uuid=$(uuidgen)
    sed -i '' -e "s/id = \"[a-zA-Z0-9-]\{36\}\"/id = \"${uuid}\"/g" $i
done

对于一般情况，问题仍然存在，如果可以一次性完成。

在Linux和OSX上用唯一的guid替换每个匹配值的文本

2 个答案: