查找执行删除: 没有此文件或目录

Question

为什么以下示例会出现“找不到文件或目录”的错误？ 有一些解决方法可以避免出现此错误，但问题在于为什么在这个确切的示例中会产生该错误。

cd /tmp
mkdir -p TOP1/AB/AC/AD/AE/AF
mkdir -p TOP2/AB/AC/AD/AE/AF

find . -iname 'A*' -exec rm -rvf {} \;
removed directory: `./TOP1/AB/AC/AD/AE/AF'
removed directory: `./TOP1/AB/AC/AD/AE'
removed directory: `./TOP1/AB/AC/AD'
removed directory: `./TOP1/AB/AC'
removed directory: `./TOP1/AB'
find: `./TOP1/AB': No such file or directory
removed directory: `./TOP2/AB/AC/AD/AE/AF'
removed directory: `./TOP2/AB/AC/AD/AE'
removed directory: `./TOP2/AB/AC/AD'
removed directory: `./TOP2/AB/AC'
removed directory: `./TOP2/AB'
find: `./TOP2/AB': No such file or directory

使用 -depth 或 \+ 或 -delete 可解决此问题：

find .        -iname 'A*' -exec rm -rvf {} \+
find . -depth -iname 'A*' -exec rm -rvf {} \;
find . -iname 'A*' -delete

- pmoubed

---

尝试手动删除./TOP1/AB后面跟着的./TOP1/AB/AC。当你到达./TOP1/AB/AC时，你会发现这个文件或目录不存在（因为你已经在删除./TOP1/AB时一并删除了它）。 - that other guy

如果使用GNU find命令，可以使用"-delete"代替"-exec rm ..."。 - Shawn

-删除意味着深度 - pmoubed

@thatotherguy 在不存在的文件夹上执行 rm -rf 不会报错！试试执行 rm -rf somthing-that-does-not-exist，你不会得到 No such file or directory 的提示。 - pmoubed

Answer 1

我认为答案就在手册页中: https://linux.die.net/man/1/find

此外请参考\;和+: Using semicolon (;) vs plus (+) with exec in find

为了更好地理解整个过程，您可以将文件打印出来而不是删除它们。以TOP1文件夹为例:

find . -iname 'A*' -exec echo "{}" \;

输出：

./TOP1/AB
./TOP1/AB/AC
./TOP1/AB/AC/AD
./TOP1/AB/AC/AD/AE
./TOP1/AB/AC/AD/AE/AF

\; 的作用是：在当前目录下或其子目录中运行每个文件。这里的顺序很重要，即首先处理父文件夹，然后递归遍历其子文件夹。

另一方面，rm -frv 的工作原理如下：

rm -frv ./TOP1

输出：

removed directory './TOP1/AB/AC/AD/AE/AF'
removed directory './TOP1/AB/AC/AD/AE'
removed directory './TOP1/AB/AC/AD'
removed directory './TOP1/AB/AC'
removed directory './TOP1/AB'
removed directory './TOP1'

rm -fr 与 find 实际上的运行方式相反，这是本问题的主要原因:

find 结合 \; 首先从父文件夹 TOP1 开始，在此文件夹中，由于 -exec rm -rvf {} \; 这一部分的作用，文件夹 TOP1 及其内容将被完全删除。在下一轮中，find 然后尝试处理下面的子文件夹，显然它首先通过 stat ./TOP1 检查基础文件夹是否仍存在，只有在检测到存在时才会进入更深一层。但由于 ./TOP1 在第一轮中已经被删除，stat ./TOP1 将失败，因此出现错误信息。

使用 其他可用参数 来改变默认行为：

• -depth: 在处理(父)目录本身之前处理每个目录的内容。-delete动作也意味着-depth。 (即从底部到顶部遍历，就像 rm -fr 一样！)
• -delete: -delete选项的使用自动打开了-depth选项。
• 使用 +: 只执行一次 -exec rm -rvf {} + 部分，例如 -exec rm -rvf {} +:

rm -frv ./TOP1/AB ./TOP1/AB/AC ./TOP1/AB/AC/AD ./TOP1/AB/AC/AD/AE ./TOP1/AB/AC/AD/AE/AF

最后但同样重要的一点是： 当使用rm命令加上-fr参数时，它会变得非常"宽容"，不会抛出任何错误。它将尝试强制性地和递归地删除传递给它的所有内容；如果遇到不存在的文件/目录，它也不会报错。

- Kenan Güler

Answer 2

这是find的一个实现细节。你可以在它的源代码中找到你问题的最终答案。

在Linux上，了解背后发生的事情的另一种方法是strace。我准备了一些有趣的strace输出。你可以看一下两个find调用（带和不带-depth）发出的openat系统调用的顺序。

mkdir -pv TOP{1,2}/AB/AC/AD/AE/AF && strace -o foo find . -depth -iname 'A*' -exec rm -rvf {} \; ; grep openat foo
mkdir: created directory 'TOP1/AB'
mkdir: created directory 'TOP1/AB/AC'
mkdir: created directory 'TOP1/AB/AC/AD'
mkdir: created directory 'TOP1/AB/AC/AD/AE'
mkdir: created directory 'TOP1/AB/AC/AD/AE/AF'
mkdir: created directory 'TOP2/AB'
mkdir: created directory 'TOP2/AB/AC'
mkdir: created directory 'TOP2/AB/AC/AD'
mkdir: created directory 'TOP2/AB/AC/AD/AE'
mkdir: created directory 'TOP2/AB/AC/AD/AE/AF'
removed directory './TOP1/AB/AC/AD/AE/AF'
removed directory './TOP1/AB/AC/AD/AE'
removed directory './TOP1/AB/AC/AD'
removed directory './TOP1/AB/AC'
removed directory './TOP1/AB'
removed directory './TOP2/AB/AC/AD/AE/AF'
removed directory './TOP2/AB/AC/AD/AE'
removed directory './TOP2/AB/AC/AD'
removed directory './TOP2/AB/AC'
removed directory './TOP2/AB'
5:openat(AT_FDCWD, "/etc/ld.so.cache", O_RDONLY|O_CLOEXEC) = 3
9:openat(AT_FDCWD, "/lib/x86_64-linux-gnu/libselinux.so.1", O_RDONLY|O_CLOEXEC) = 3
20:openat(AT_FDCWD, "/lib/x86_64-linux-gnu/libm.so.6", O_RDONLY|O_CLOEXEC) = 3
28:openat(AT_FDCWD, "/lib/x86_64-linux-gnu/libc.so.6", O_RDONLY|O_CLOEXEC) = 3
44:openat(AT_FDCWD, "/usr/lib/x86_64-linux-gnu/libpcre2-8.so.0", O_RDONLY|O_CLOEXEC) = 3
52:openat(AT_FDCWD, "/lib/x86_64-linux-gnu/libdl.so.2", O_RDONLY|O_CLOEXEC) = 3
60:openat(AT_FDCWD, "/lib/x86_64-linux-gnu/libpthread.so.0", O_RDONLY|O_CLOEXEC) = 3
93:openat(AT_FDCWD, "/proc/filesystems", O_RDONLY|O_CLOEXEC) = 3
99:openat(AT_FDCWD, ".", O_RDONLY|O_CLOEXEC) = 3
102:openat(AT_FDCWD, "/usr/lib/locale/locale-archive", O_RDONLY|O_CLOEXEC) = 4
106:openat(AT_FDCWD, "/usr/lib/x86_64-linux-gnu/gconv/gconv-modules.cache", O_RDONLY) = 4
114:openat(AT_FDCWD, ".", O_RDONLY|O_NOCTTY|O_NONBLOCK|O_NOFOLLOW|O_CLOEXEC|O_DIRECTORY) = 4
125:openat(5, "TOP1", O_RDONLY|O_NOCTTY|O_NONBLOCK|O_NOFOLLOW|O_CLOEXEC|O_DIRECTORY) = 6
137:openat(7, "AB", O_RDONLY|O_NOCTTY|O_NONBLOCK|O_NOFOLLOW|O_CLOEXEC|O_DIRECTORY) = 6
149:openat(8, "AC", O_RDONLY|O_NOCTTY|O_NONBLOCK|O_NOFOLLOW|O_CLOEXEC|O_DIRECTORY) = 6
161:openat(9, "AD", O_RDONLY|O_NOCTTY|O_NONBLOCK|O_NOFOLLOW|O_CLOEXEC|O_DIRECTORY) = 6
173:openat(10, "AE", O_RDONLY|O_NOCTTY|O_NONBLOCK|O_NOFOLLOW|O_CLOEXEC|O_DIRECTORY) = 6
186:openat(11, "AF", O_RDONLY|O_NOCTTY|O_NONBLOCK|O_NOFOLLOW|O_CLOEXEC|O_DIRECTORY) = 5
223:openat(8, "..", O_RDONLY|O_NOCTTY|O_NONBLOCK|O_NOFOLLOW|O_CLOEXEC|O_DIRECTORY) = 5
231:openat(5, "..", O_RDONLY|O_NOCTTY|O_NONBLOCK|O_NOFOLLOW|O_CLOEXEC|O_DIRECTORY) = 6
237:openat(6, "TOP2", O_RDONLY|O_NOCTTY|O_NONBLOCK|O_NOFOLLOW|O_CLOEXEC|O_DIRECTORY) = 5
249:openat(7, "AB", O_RDONLY|O_NOCTTY|O_NONBLOCK|O_NOFOLLOW|O_CLOEXEC|O_DIRECTORY) = 5
261:openat(8, "AC", O_RDONLY|O_NOCTTY|O_NONBLOCK|O_NOFOLLOW|O_CLOEXEC|O_DIRECTORY) = 5
273:openat(9, "AD", O_RDONLY|O_NOCTTY|O_NONBLOCK|O_NOFOLLOW|O_CLOEXEC|O_DIRECTORY) = 5
285:openat(10, "AE", O_RDONLY|O_NOCTTY|O_NONBLOCK|O_NOFOLLOW|O_CLOEXEC|O_DIRECTORY) = 5
298:openat(11, "AF", O_RDONLY|O_NOCTTY|O_NONBLOCK|O_NOFOLLOW|O_CLOEXEC|O_DIRECTORY) = 5
332:openat(8, "..", O_RDONLY|O_NOCTTY|O_NONBLOCK|O_NOFOLLOW|O_CLOEXEC|O_DIRECTORY) = 5
340:openat(5, "..", O_RDONLY|O_NOCTTY|O_NONBLOCK|O_NOFOLLOW|O_CLOEXEC|O_DIRECTORY) = 6




mkdir -pv TOP{1,2}/AB/AC/AD/AE/AF && strace -o foo find . -iname 'A*' -exec rm -rvf {} \; ; grep openat foo
mkdir: created directory 'TOP1/AB'
mkdir: created directory 'TOP1/AB/AC'
mkdir: created directory 'TOP1/AB/AC/AD'
mkdir: created directory 'TOP1/AB/AC/AD/AE'
mkdir: created directory 'TOP1/AB/AC/AD/AE/AF'
mkdir: created directory 'TOP2/AB'
mkdir: created directory 'TOP2/AB/AC'
mkdir: created directory 'TOP2/AB/AC/AD'
mkdir: created directory 'TOP2/AB/AC/AD/AE'
mkdir: created directory 'TOP2/AB/AC/AD/AE/AF'
removed directory './TOP1/AB/AC/AD/AE/AF'
removed directory './TOP1/AB/AC/AD/AE'
removed directory './TOP1/AB/AC/AD'
removed directory './TOP1/AB/AC'
removed directory './TOP1/AB'
find: ‘./TOP1/AB’: No such file or directory
removed directory './TOP2/AB/AC/AD/AE/AF'
removed directory './TOP2/AB/AC/AD/AE'
removed directory './TOP2/AB/AC/AD'
removed directory './TOP2/AB/AC'
removed directory './TOP2/AB'
find: ‘./TOP2/AB’: No such file or directory
5:openat(AT_FDCWD, "/etc/ld.so.cache", O_RDONLY|O_CLOEXEC) = 3
9:openat(AT_FDCWD, "/lib/x86_64-linux-gnu/libselinux.so.1", O_RDONLY|O_CLOEXEC) = 3
20:openat(AT_FDCWD, "/lib/x86_64-linux-gnu/libm.so.6", O_RDONLY|O_CLOEXEC) = 3
28:openat(AT_FDCWD, "/lib/x86_64-linux-gnu/libc.so.6", O_RDONLY|O_CLOEXEC) = 3
44:openat(AT_FDCWD, "/usr/lib/x86_64-linux-gnu/libpcre2-8.so.0", O_RDONLY|O_CLOEXEC) = 3
52:openat(AT_FDCWD, "/lib/x86_64-linux-gnu/libdl.so.2", O_RDONLY|O_CLOEXEC) = 3
60:openat(AT_FDCWD, "/lib/x86_64-linux-gnu/libpthread.so.0", O_RDONLY|O_CLOEXEC) = 3
93:openat(AT_FDCWD, "/proc/filesystems", O_RDONLY|O_CLOEXEC) = 3
99:openat(AT_FDCWD, ".", O_RDONLY|O_CLOEXEC) = 3
102:openat(AT_FDCWD, "/usr/lib/locale/locale-archive", O_RDONLY|O_CLOEXEC) = 4
106:openat(AT_FDCWD, "/usr/lib/x86_64-linux-gnu/gconv/gconv-modules.cache", O_RDONLY) = 4
114:openat(AT_FDCWD, ".", O_RDONLY|O_NOCTTY|O_NONBLOCK|O_NOFOLLOW|O_CLOEXEC|O_DIRECTORY) = 4
125:openat(5, "TOP1", O_RDONLY|O_NOCTTY|O_NONBLOCK|O_NOFOLLOW|O_CLOEXEC|O_DIRECTORY) = 6
142:openat(7, "AB", O_RDONLY|O_NOCTTY|O_NONBLOCK|O_NOFOLLOW|O_CLOEXEC|O_DIRECTORY) = -1 ENOENT (No such file or directory)
143:openat(AT_FDCWD, "/usr/share/locale/locale.alias", O_RDONLY|O_CLOEXEC) = 6
148:openat(AT_FDCWD, "/usr/share/locale/en_US/LC_MESSAGES/findutils.mo", O_RDONLY) = -1 ENOENT (No such file or directory)
149:openat(AT_FDCWD, "/usr/share/locale/en/LC_MESSAGES/findutils.mo", O_RDONLY) = -1 ENOENT (No such file or directory)
150:openat(AT_FDCWD, "/usr/share/locale-langpack/en_US/LC_MESSAGES/findutils.mo", O_RDONLY) = -1 ENOENT (No such file or directory)
151:openat(AT_FDCWD, "/usr/share/locale-langpack/en/LC_MESSAGES/findutils.mo", O_RDONLY) = -1 ENOENT (No such file or directory)
154:openat(AT_FDCWD, "/usr/share/locale/en_US/LC_MESSAGES/libc.mo", O_RDONLY) = -1 ENOENT (No such file or directory)
155:openat(AT_FDCWD, "/usr/share/locale/en/LC_MESSAGES/libc.mo", O_RDONLY) = -1 ENOENT (No such file or directory)
156:openat(AT_FDCWD, "/usr/share/locale-langpack/en_US/LC_MESSAGES/libc.mo", O_RDONLY) = -1 ENOENT (No such file or directory)
157:openat(AT_FDCWD, "/usr/share/locale-langpack/en/LC_MESSAGES/libc.mo", O_RDONLY) = -1 ENOENT (No such file or directory)
164:openat(5, "TOP2", O_RDONLY|O_NOCTTY|O_NONBLOCK|O_NOFOLLOW|O_CLOEXEC|O_DIRECTORY) = 6
179:openat(7, "AB", O_RDONLY|O_NOCTTY|O_NONBLOCK|O_NOFOLLOW|O_CLOEXEC|O_DIRECTORY) = -1 ENOENT (No such file or directory)

- hek2mgl