Implement touch using Python?
This tries to be a little more race-free than the other solutions. (The with
keyword is new in Python 2.5.)
import os
def touch(fname, times=None):
with open(fname, 'a'):
os.utime(fname, times)
Roughly equivalent to this.
import os
def touch(fname, times=None):
fhandle = open(fname, 'a')
try:
os.utime(fname, times)
finally:
fhandle.close()
Now, to really make it race-free, you need to use futimes
and change the timestamp of the open filehandle, instead of opening the file and then changing the timestamp on the filename (which may have been renamed). Unfortunately, Python doesn't seem to provide a way to call futimes
without going through ctypes
or similar...
EDIT
As noted by Nate Parsons, Python 3.3 will add specifying a file descriptor (when os.supports_fd
) to functions such as os.utime
, which will use the futimes
syscall instead of the utimes
syscall under the hood. In other words:
import os
def touch(fname, mode=0o666, dir_fd=None, **kwargs):
flags = os.O_CREAT | os.O_APPEND
with os.fdopen(os.open(fname, flags=flags, mode=mode, dir_fd=dir_fd)) as f:
os.utime(f.fileno() if os.utime in os.supports_fd else fname,
dir_fd=None if os.supports_fd else dir_fd, **kwargs)
Looks like this is new as of Python 3.4 - pathlib
.
from pathlib import Path
Path('path/to/file.txt').touch()
This will create a file.txt
at the path.
--
Path.touch(mode=0o777, exist_ok=True)
Create a file at this given path. If mode is given, it is combined with the process’ umask value to determine the file mode and access flags. If the file already exists, the function succeeds if exist_ok is true (and its modification time is updated to the current time), otherwise FileExistsError is raised.