$ composer require server --dev
Restricting packages listed in "symfony/symfony" to "4.4.*"
./composer.json has been updated
Loading composer repositories with package information
Updating dependencies (including require-dev)
Restricting packages listed in "symfony/symfony" to "4.4.*"
Nothing to install or update
Writing lock file
Generating autoload files
ocramius/package-versions: Generating version class...
ocramius/package-versions: ...done generating version class
Executing script cache:clear [KO]
[KO]
Script cache:clear returned with error code 1
!!
!! In Kernel.php line 547:
!!
!! Notice: fwrite(): write of 785 bytes failed with errno=13 Permission denied
!!
!!
!!
Script @auto-scripts was called via post-update-cmd
Installation failed, reverting ./composer.json to its original content.
答案 0 :(得分：-1)
!! Notice: fwrite(): write of 785 bytes failed with errno=13 Permission denied
该消息很清楚，您当前的用户没有足够的权限来编写composer dir。
也许composer install已以root用户身份运行？