Shell script to ping/see if port 80 is open?

[Johnsie]

Hi, I'm looking to write a shell script that will ping port 80 of localhost

If port 80 is closed then the script should send an email to email warning that apache has crashed.

Can anyone help point me in the right direction?

[roccivic]

echo -n "GET / HTTP/1.0\r\n\r\n" | nc 127.0.0.1 80 || /path/to/emailing/script

This will try to send a GET request to 127.0.0.1 at port 80, if there is no reply it will run the script found at "/path/to/emailing/script"

Schedule it as a cron job.

Hope this helps...

[bashologist]

Great solution very nice and simple. But wouldn't you want echo to interprate the escapes? If I'm right then this might be the correct way.

echo -e "GET / HTTP/1.0\r\n\r" | nc 127.0.0.1 80 || /path/to/emailing/script

I could be wrong.

Edit:
Another possibility...

echo GET / | nc 127.0.0.1 80

[Cheesehead]

netstat -tupln | grep :80