4 ms·

To be fair, `cp baz bar` is the only one of those commands that might take three hours.

• vidarh 14y ago
  That's not true. mv across filesystems degrades to a copy, and can take just as long.
  • wtallis 14y ago
    And CoW filesystems are getting more common, so cp's best case can be almost as fast as mv's.
    • loeg 14y ago
      Really? After some quick digging, nope. Tl;dr: Not by default, and only on Linux, and only with btrfs (still marked experimental) and only with the `--reflink` flag. FreeBSD `cp(1)`: `copy_file()` does a simple `read()`/`write()` loop with a buffer[0] (despite ZFS maybe supporting CoW). GNU coreutils `cp(1)`: `copy_reg()` calls out to `clone_file()` if and only if `--reflink` was passed[1], and `clone_file()` fails on everything but btrfs[2]. [0]: FreeBSD `copy_file()`: https://github.com/freebsd/freebsd/blob/master/bin/cp/utils.c#L205 https://github.com/freebsd/freebsd/blob/master/bin/cp/utils.... [1]: coreutils `copy_reg()`: http://git.savannah.gnu.org/gitweb/?p=coreutils.git;a=blob;f=src/copy.c;h=5c0ee1e703d8494b71eda67436a12c5d79a9a5ef;hb=HEAD#l978 http://git.savannah.gnu.org/gitweb/?p=coreutils.git;a=blob;f... [2]: coreutils `clone_file()`: http://git.savannah.gnu.org/gitweb/?p=coreutils.git;a=blob;f=src/copy.c;h=5c0ee1e703d8494b71eda67436a12c5d79a9a5ef;hb=HEAD#l223 http://git.savannah.gnu.org/gitweb/?p=coreutils.git;a=blob;f...