Veja o script corrigido:
#!/bin/bash
## the driver's name
drivername=$(lspci -vv -s $(lspci |grep -i ethernet| awk -F" " '{print $1}')| awk -F" " '/driver/ {print $5}')
checkout ()
{
lsmod > tmp.txt
if grep -i $drivername "tmp.txt" > /dev/null ; then
echo "there's a driver called: $drivername"
exit 0
else
echo "there's not any driver"
exit 1
fi
}
checkout $drivername;