If with variable state [duplicate]

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• How to compare strings in Bash script 8 answers

I have a bash script and variable $manufacturer_string within, which can have many values and need to write correct if statement, to determine, in which file, I need to write another variable $device_manufacturer0:

if manufacturer_string=Not_supported_devices; then
    echo "$device_manufacturer0" >> $DIR/ToAddSysObjectID_list.txt 
elif manufacturer_string="any other value"
    echo "$device_manufacturer0" >> $DIR/KnownSysObjectID_list.txt

How to write correctly elif statement, if value of $manufacturer_string is not a "Not_supported_devices"?