What flag should be used for permission searches in Linux?

The flag that should be used for permission searches in Linux is -perm. This option is specifically designed to find files based on their permission settings. When using the find command, for instance, the -perm flag allows the user to specify the exact permission mode to search for, or combinations involving the permission bits like user, group, or other permissions.

For example, if you wanted to find files that are readable and writable by the owner, you could use a command like find /path/to/dir -perm 600. This command will return all files under the specified directory that match the permission settings.

The other options do not represent valid flags for this purpose. -p does not relate to permissions but is used in some contexts for different command features. -permissions and -access are not recognized flags in typical Linux command usage for file permission searches. Therefore, -perm clearly stands out as the appropriate choice for conducting permission-based searches in Linux.