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如何删除临时文件而不更改目录的修改时间戳？

tag-icon • tag-icon directory timestamps
如何删除临时文件而不更改目录的修改时间戳？

我研究测试用例，每个测试用例都是~/test.可以很方便地查看我最近使用类似ls -rtl.现在我想从测试目录中删除某些临时文件；唉，这会改变目录的时间戳。

是否可以从目录中删除文件而不更改目录的修改时间戳？

答案1

删除文件后，您必须重置目录上的时间戳。假设使用 GNU 工具，类似这样的东西应该可以工作：

mtime=$(stat -c %y dir)            # get the timestamp, store in $mtime
rm dir/somefile dir/someotherfile  # do whatever you need
touch -d "$mtime" dir              # set the timestamp back

这会将目录上的修改 ( mtime) 和访问 ( ) 时间戳重置为原始修改时间戳，同时还将更改时间戳 ( ) 设置为当前时间。更改是不可避免的，但您可能不关心它或。atimectimectimeatime

答案2

该touch命令提供了-r允许您触摸与参考文件具有相同时间戳的文件的选项。因此，您可以这样做：

touch -r /dir/somefile /tmp/_thetimestamps  # save the timestamps in /tmp/_thetimestamps
rm /dir/somefile                            # do whatever you need
touch -r /tmp/_thetimestamps /dir           # set the timestamps back

Linux人:

-r, --reference=FILE
      use this file's times instead of current time

Unix人:

-r       Use the access and modifications times from the specified file
         instead of the current time of day.

答案3

这是 Python 版本ikkachu 的精彩回答:

https://gist.github.com/jaytaylor/ea1b6082ea5bcea7a6b65518d91238f5

#!/usr/bin/env python
# -*- coding: utf-8 -*-

"""
Removes a file or directory while preserving the modification time (mtime) of
the parent directory.

Pure-python implementation.

See also:
    https://unix.stackexchange.com/a/565595/22709
"""

import argparse
import logging
import os
import platform
import re
import shutil
import stat
import sys

log_formatter = logging.Formatter('%(asctime)s, %(levelname)s %(message)s')

logging.basicConfig(level=logging.INFO, formatter=log_formatter)
logger = logging.getLogger(__name__)

def parse_opts(args):
    parser = argparse.ArgumentParser(
        description='Removes a file or directory while preserving the modification time (mtime) of the parent directory.',
        argument_default=False,
    )
    parser.add_argument('-f', '--force', default=False, action='store_true', help='Ignore nonexistent files and arguments')
    parser.add_argument('-i', '--interactive', default=False, action='store_true', help='Prompt for confirmation before taking action on a target')
    parser.add_argument('--no-preserve-root', default=False, action='store_true', help="Do not treat '/' specially")
    parser.add_argument('-r', '--recursive', default=False, action='store_true', help='Remove directories and their contents recursively')
    parser.add_argument('-v', '--verbose', default=False, action='store_true', help='Display verbose log output')
    parser.add_argument('paths', type=str, nargs='+', help='Filesystem path(s) to remove')

    opts = parser.parse_args(args)
    if opts.verbose:
        logger.setLevel(logging.DEBUG)

    return opts

# n.b. Use the appropriate input function depending on whether the runtime
#      environment is Python version 2 or 3.
_input_fn = input if sys.version_info > (3, 0) else raw_input

def _prompt_for_confirmation(path, opts):
    if not opts.interactive:
        return True

    response = _input_fn('Permanently remove "%s"? (Y/n)' % (path,))
    return response in ('Y', 'y')

def require_write_permissions(path):
    parent = os.path.dirname(path)
    if not os.access(parent, os.W_OK):
        raise Exception('Missing necessary write permission for parent directory "%s"; operation aborted' % (parent,))

def rm_preserving_parent_mtime(path, opts):
    """
    Deletes the specified path, and restores the filesystem access and modified
    timestamp values afterward removing path.

    IMPORTANT
    ---------
    Take note of the permission test before removing the target. These checks
    verify write access to parent's parent.

    Without the check, there is a risk that the file will be removed and then
    setting mtime fails.  When this happens, the entire purpose of this program is defeated.
    """
    if not opts.no_preserve_root and (path == os.sep or (platform.system() == 'Windows' and re.match(r'^[A-Z]:%s?' % (os.sep,), path))):
        raise Exception('Cowardly refusing to operate on root path')

    if path in ('', '.', '..'):
        raise Exception('Invalid path "%s", must have a parent directory' % (path,))

    parent = os.path.dirname(path)

    if path == parent:
        raise Exception('Invalid path, parent directory="%s" should not equal path="%s"' % (parent, path))

    st = os.stat(parent)
    atime = st[stat.ST_ATIME]
    mtime = st[stat.ST_MTIME]

    modified = False

    try:
        if os.path.isfile(path):
            require_write_permissions(parent)
            if _prompt_for_confirmation(path, opts):
                logger.debug('Removing file "%s"' % (path,))
                modified = True
                os.remove(path)
        elif os.path.isdir(path):
            if not opts.recursive:
                raise Exception('Cannot remove "%s": Is a directory' % (path,))
            require_write_permissions(parent)
            if _prompt_for_confirmation(path, opts):
                logger.debug('Removing directory "%s"' % (path,))
                modified = True
                shutil.rmtree(path)
        else:
            raise Exception('Path "%s" is not a file or directory' % (path,))
    finally:
        if modified:
            logger.debug('Restoring access and modification timestamps for parent="%s"' % (parent,))
            os.utime(parent, (atime, mtime))

def main(paths, opts):
    try:
        for path in paths:
            rm_preserving_parent_mtime(path, opts)
        return 0
    except BaseException:
        logger.exception('Caught exception in main')
        if opts.force:
            return 0
        return 1

if __name__ == '__main__':
    opts = parse_opts(sys.argv[1:])
    sys.exit(main(opts.paths, opts))

有关在保留父目录 mtime 的同时移动或删除文件的完整解决方案，请参阅以下 python 脚本：https://gist.github.com/jaytaylor/e2e0b53baf224f4e973b252370499de7

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