The following commands can help you confirm that the new RAID adapter has been recognized by the Linux system:
dmesg: This command displays the kernel messages, which can show the information about the newly detected hardware device. You can use dmesg | grep -i raid to filter the output for RAID-related messages.
lshw -class disk: This command lists the disk devices on the system, including the RAID controller and its model name. You can use lshw -class disk | grep -i raid to filter the output for RAID-related information1.
The other commands are not relevant for this purpose. For example:
rmmod: This command removes a module from the Linux kernel, which is not useful for detecting a new device.
ls -l /etc: This command lists the files and directories in the /etc directory, which is not related to hardware devices.
pvdisplay: This command displays the attributes of physical volumes, which are part of the logical volume management (LVM) system, not the RAID system.
rmdir /dev: This command removes an empty directory, which is not helpful for detecting a new device. Moreover, /dev is a special directory that contains device files, and should not be removed.