我以为我明白这一点，但我得到了无法解释的行为。我有这些文件：
$ which -a kvm | xargs ls -l
lrwxrwxrwx 1 root root 18 2011-11-17 17:14 /usr/bin/kvm -> qemu-system-x86_64
lrwxrwxrwx 1 root root 18 2011-11-17 17:21 /usr/local/bin/kvm -> qemu-system-x86_64
$ which -a qemu-system-x86_64 | xargs ls -l
-rwxr-xr-x 1 root root 2535168 2011-10-04 02:44 /usr/bin/qemu-system-x86_64
-rwxr-xr-x 1 root root 3497304 2011-11-17 16:26 /usr/local/bin/qemu-system-x86_64
它们是不同的版本：
$ /usr/bin/kvm --version
QEMU PC emulator version 0.12.3 (qemu-kvm-0.12.3), Copyright (c) 2003-2008 Fabrice Bellard
$ /usr/local/bin/kvm --version
QEMU emulator version 0.15.92 (qemu-kvm-devel), Copyright (c) 2003-2008 Fabrice …