setfacl:tldr:ae9e3

The command "setfacl -d -m u::rw ${file}" is used to modify the default Access Control List (ACL) entry for a specific file (${file}). Here's a breakdown of the different components of this command:

• "setfacl": This is the command for modifying file ACLs on Linux systems. It stands for "Set File ACL".
• "-d": This option tells setfacl to modify the default ACL entry for the given file. Default ACLs define the initial set of permissions applied to newly created files or directories within a particular directory.
• "-m": This option is used to modify the ACL entry.
• "u::rw": This is the ACL entry being set or modified. It consists of three parts: the entity (u for the user owner), the permissions (::), and the permissions itself (rw for read and write access). In this case, it grants the user owner read and write permissions to the file.
• "${file}": This is the placeholder for the specific file to which the ACL entry is applied. You should replace ${file} with the actual path and filename.

Overall, the command adds or modifies the default ACL entry for the specified file, granting read and write permissions to the user owner. This means that any new files or directories created within the same directory as ${file} will inherit these permissions by default.