active_serial=$(grep "serial" /proc/tty/drivers | cut -d/ -f1 | sed "s/ *$//")
# Rephrase input parameter from ttyS target index (ttyS1, ttyS2, ttyAMA0, etc).
-runtime_tty=$(echo $2 | grep -oh '[0-9]')
+runtime_tty=$(echo $2 | grep -oh '[0-9]\+')
# busybox' getty does this itself, util-linux' agetty needs extra help
getty="/sbin/getty"
then
# Remove all unknown entries and discard the first line (desc).
activetty=$(grep -v "unknown" "/proc/tty/driver/$line" \
- | tail -n +2 | grep -oh "^\s*\S*[0-9]")
+ | tail -n +2 | grep -oh "^\s*\S*[0-9]\+")
for active in $activetty; do
# If indexes do match then enable the serial console.
if [ $active -eq $runtime_tty ]