Bash loop ping successful

Question

I'm thinking that this needs to be changed to a while clause, at the moment it'll wait till all 10000 pings are done, I need it to return when the ping is successful. The program "say" is on OSX it makes the computer speak.

#!/bin/bash echo begin ping if ping -c 100000 8.8.8.8 | grep timeout; then echo `say timeout`; else echo `say the internet is back up`; fi 

OK I don't have rights to answer my own question so here's my answer for it after playing around:

Thanks, yeah I didn't know about $? until now. Anyway now I've gone and made this. I like that yours doesn't go forever but in my situation I didn't need it to stop until it's finished.

#!/bin/bash intertube=0 echo "begin ping" while [ $intertube -ne 1 ]; do         ping -c 3 google.com         if [ $? -eq  0 ]; then                 echo "ping success";                 say success                 intertube=1;         else                 echo "fail ping"         fi done echo "fin script" 

Answer 1

You probably shouldn't rely on textual output of a command to decide this, especially when the ping command gives you a perfectly good return value:

The ping utility returns an exit status of zero if at least one response was heard from the specified host; a status of two if the transmission was successful but no responses were received; or another value from <sysexits.h> if an error occurred.

In other words, use something like:

((count = 60))                           # Maximum number to try. while [[ $count -ne 0 ]] ; do     ping -c 1 8.8.8.8                    # Try once.     rc=$?     if [[ $rc -eq 0 ]] ; then         ((count = 1))                    # If okay, flag loop exit.     else         sleep 1                          # Minimise network storm.     fi     ((count = count - 1))                # So we don't go forever. done  if [[ $rc -eq 0 ]] ; then                # Make final determination.     echo `say The internet is back up.` else     echo `say Timeout.` fi