Force device rescan (see detect_sata.sh)

rescan.sh

#!/bin/bash
set -e
# Note: 2021-09-09:
# I ran this script and scanned only the hosts that weren't listing a device
# However, it didn't find the block that I needed it to, until I did a global scan:
# ls /sys/class/scsi_host/ | while read host ; do echo "- - -" > /sys/class/scsi_host/$host/scan ; done
# I know this feels dangerous, I would avoid doing it if I understood what was going on, but I eventually just gave up.
# I think there's something wrong below with the matching of the `readlink /sys/block`
# After the full scan, two drives had the same 'host', so I'm not sure if that was the issue or what.

if [ "$(whoami)" != "root" ]; then
    echo "Must be root"
    exit 1
fi

scan_bus() {
    path="$1"
    if [ ! -e "$path" ]; then
        echo "Does not exist: $path"
    fi
    if yes_no "Do you want to scan $path?"; then
        echo "0 0 0" > "$path"
        echo "done"
    else
        echo "Canceled"
    fi
}



source ~/.bin/bash_aliases/confirm.sh

if yes_no "Scan Existing drive?"; then
    read -p "Scan: " device

    [ -b "$device" -o -b /dev/"$device" ] || { echo "Error: Invalid device '$device'"; exit 1; }

    device=$(basename $(echo "$device" |sed -e 's/[0-9]$//g'))
    host=$(ls -l /sys/block/$device/subsystem/ |grep "${device}$" |grep -oE 'host[0-9]+')

    read -p "Rescan device or bus?: (D/b) " yn
    case $yn in
      d|D)
        # Rescan the specific device
        echo 1 > /sys/block/$device/device/rescan
        ;;

      b|B)
        # Rescan the bus
        scan_bus "/sys/class/scsi_host/$host/scan"
        ;;

      *) echo "Invalid option. Quitting"; exit 1;;
    esac
else
    for i in $(ls /dev/); do
        if [[ "$i" =~ "sd" ]]; then
            (echo -n "$i => "; readlink /sys/block/$i | cut -d '/' -f 6; echo "") | grep "host" || echo -n ''
        fi
    done
    echo "Here are all of them: $(echo $(ls /sys/class/scsi_host))"
    read -p "Which bus do you want to scan? (Which one is missing) " bus
    full_bus="/sys/class/scsi_host/$bus/scan"
    scan_bus "$full_bus"
fi