不用买讲bash的书

到 NJU Mirror (国内镜像)下个bash-5.1.tar.gz, 10MB，doc目录下的*.pdf和*.html就够看的了。examples下还有一堆例子。

Access Control List好像Linux早就支持了:

POSIX ACLs in Linux - Linux.com

linux - How do I know ACLs are supported on my file system? - Unix & Linux Stack Exchange

# file: acldir
# owner: foo
# group: bar
user::rwx # 我觉得是owner::rwx的意思。但要和过去的owner-group-other兼容
user:scooby:rwx
group::r-x
group:doo:rwx
mask::rwx
other::---