在 Plan 9 rcshell 中，可以编写
echo (foo bar baz)^.c
要得到
foo.c bar.c baz.c
或者
echo (foo bar baz)^(.c .h .o)
要得到
foo.c bar.h baz.o
在 Bash 中是否有与此等价的功能？具体来说，有没有比前者更快
`for f in foo bar baz; do echo $f.c; done`
的方法，后者有没有这样的方法？
我目前在我的计算机上运行 Debian Buster 作为测试。现在 Buster 已经稳定了，我应该如何更新我的系统？
具体来说，我该如何配置/etc/apt/sources.list？
目前，它看起来像这样：
# deb cdrom:[Official Debian GNU/Linux Live 9.9.0 xfce 2019-04-27T10:47]/ stretch main
# deb cdrom:[Official Debian GNU/Linux Live 9.9.0 xfce 2019-04-27T10:47]/ stretch main
deb http://ftp.uk.debian.org/debian/ buster main
deb-src http://ftp.uk.debian.org/debian/ buster main
deb http://security.debian.org/debian-security/ buster/updates main
deb-src http://security.debian.org/debian-security/ buster/updates main
#stretch-updates, previously known as 'volatile'
deb http://ftp.uk.debian.org/debian/ buster-updates main
deb-src http://ftp.uk.debian.org/debian/ buster-updates main
当我运行时，sudo apt-get update我得到这个输出：
Ign:1 http://deb.debian.org/debian stretch InRelease
Get:2 http://security.debian.org/debian-security buster/updates InRelease [31.1 kB]
Get:3 http://ftp.uk.debian.org/debian buster InRelease [118 kB]
Get:4 http://deb.debian.org/debian stretch Release [118 kB]
Get:5 http://ftp.uk.debian.org/debian buster-updates InRelease [46.8 kB]
Get:6 http://deb.debian.org/debian stretch Release.gpg [2,434 B]
Reading package lists... Done
E: Repository 'http://security.debian.org/debian-security buster/updates InRelease' changed its 'Suite' value from 'testing' to 'stable'
N: This must be accepted explicitly before updates for this repository can be applied. See apt-secure(8) manpage for details.
N: Repository 'http://ftp.uk.debian.org/debian buster InRelease' changed its 'Version' value from '' to '10.0'
E: Repository 'http://ftp.uk.debian.org/debian buster InRelease' changed its 'Suite' value from 'testing' to 'stable'
N: This must be accepted explicitly before updates for this repository can be applied. See apt-secure(8) manpage for details.
E: Repository 'http://ftp.uk.debian.org/debian buster-updates InRelease' changed its 'Suite' value from 'testing-updates' to 'stable-updates'
N: This must be accepted explicitly before updates for this repository can be applied. See apt-secure(8) manpage for details.
E: Repository 'http://deb.debian.org/debian stretch Release' changed its 'Suite' value from 'stable' to 'oldstable'
N: This must be accepted explicitly before updates for this repository can be applied. See apt-secure(8) manpage for details.
更新：我运行sudo apt update并与更新管理器进行了此对话：
geoff@geoff-debian:/etc/apt$ sudo apt update
Get:1 http://ftp.uk.debian.org/debian buster InRelease [118 kB]
Get:2 http://security.debian.org/debian-security buster/updates InRelease [31.1 kB]
E: Repository 'http://security.debian.org/debian-security buster/updates InRelease' changed its 'Suite' value from 'testing' to 'stable'
N: This must be accepted explicitly before updates for this repository can be applied. See apt-secure(8) manpage for details.
Do you want to accept these changes and continue updating from this repository? [y/N] y
Get:3 http://ftp.uk.debian.org/debian buster-updates InRelease [46.8 kB]
Ign:4 http://deb.debian.org/debian stretch InRelease
Get:5 http://deb.debian.org/debian stretch Release [118 kB]
Get:6 http://security.debian.org/debian-security buster/updates/main Sources [1,688 B]
Get:7 http://deb.debian.org/debian stretch Release.gpg [2,434 B]
Get:8 http://security.debian.org/debian-security buster/updates/main amd64 Packages [1,448 B]
Get:9 http://security.debian.org/debian-security buster/updates/main Translation-en [1,364 B]
N: Repository 'http://ftp.uk.debian.org/debian buster InRelease' changed its 'Version' value from '' to '10.0'
E: Repository 'http://ftp.uk.debian.org/debian buster InRelease' changed its 'Suite' value from 'testing' to 'stable'
N: This must be accepted explicitly before updates for this repository can be applied. See apt-secure(8) manpage for details.
Do you want to accept these changes and continue updating from this repository? [y/N] y
E: Repository 'http://ftp.uk.debian.org/debian buster-updates InRelease' changed its 'Suite' value from 'testing-updates' to 'stable-updates'
N: This must be accepted explicitly before updates for this repository can be applied. See apt-secure(8) manpage for details.
Do you want to accept these changes and continue updating from this repository? [y/N] y
E: Repository 'http://deb.debian.org/debian stretch Release' changed its 'Suite' value from 'stable' to 'oldstable'
N: This must be accepted explicitly before updates for this repository can be applied. See apt-secure(8) manpage for details.
Do you want to accept these changes and continue updating from this repository? [y/N] y
Fetched 171 kB in 1min 6s (2,594 B/s)
Reading package lists... Done
Building dependency tree
Reading state information... Done
159 packages can be upgraded. Run 'apt list --upgradable' to see them.
geoff@geoff-debian:/etc/apt$
这样可以吗？我特别关注 old-stable 消息。我还应该拥有这个存储库吗？