在使用manjaro的pacman命令做系统或软件升级时，遇到了如下的报错，从而导致不能正常更新升级:
error: failed to update core (unable to lock database)
error: failed to update extra (unable to lock database)
error: failed to update community (unable to lock database)
error: failed to update multilib (unable to lock database)
error: failed to update archlinuxcn (unable to lock database)
error: failed to update antergos (unable to lock database)
error: failed to synchronize all databases
查阅相关资料后,找到原因:
这是Pacman数据库因之前的操作异常而被锁定，需要我们进行手动解锁
可执行如下命令:
rm -f /var/lib/pacman/db.lck
然后重新执行sudo pacman -Syu即可
core is up to date
extra is up to date 0.0 B 0.00B/s 00:00 [--------------------------------] 0%
community is up to date 0.0 B 0.00B/s 00:00 [--------------------------------] 0%
multilib is up to date
archlinuxcn is up to date 0.0 B 0.00B/s 00:00 [--------------------------------] 0%
antergos is up to date
:: Starting full system upgrade...
resolving dependencies...
looking for conflicting packages...
Packages (3) firefox-67.0.3-0 firefox-i18n-zh-cn-67.0.3-0 google-chrome-75.0.3770.100-1
Total Download Size: 105.17 MiB
Total Installed Size: 379.93 MiB
Net Upgrade Size: 12.15 MiB
:: Proceed with installation? [Y/n] y
:: Retrieving packages...
firefox-67.0.3-0-x86_64 46.9 MiB 26.5M/s 00:02 [################################] 100%
firefox-i18n-zh-cn-67.0.3-0-any 466.4 KiB 65.1M/s 00:00 [################################] 100%
google-chrome-75.0.3770.100... 57.8 MiB 4.21M/s 00:14 [################################] 100%
(3/3) checking keys in keyring [################################] 100%
(3/3) checking package integrity [################################] 100%
(3/3) loading package files [################################] 100%
(3/3) checking for file conflicts [################################] 100%
(3/3) checking available disk space [################################] 100%
:: Running pre-transaction hooks...
(1/1) Remove Firefox Distribution Settings
:: Processing package changes...
(1/3) upgrading firefox [################################] 100%
(2/3) upgrading firefox-i18n-zh-cn [################################] 100%
(3/3) upgrading google-chrome [################################] 100%
