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

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You don t need to use echo or grep  You could do this   ping -oc 100000 8 8 8 8  gt   dev null  amp  amp  say  up     say  down

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If you use the -o option  Mac OS X   s ping will exit after receiving one reply packet   Further reading  http   developer apple com library mac  documentation Darwin Reference ManPages man8 ping 8 html  EDIT  paxdiablo makes a very good point about using ping   s exit status to your advantage  I would do something like      usr bin env bash echo  Begin ping  if ping -oc 100000 8 8 8 8  gt   dev null  then     echo   say  timeout   else     echo   say  the Internet is back up   fi   ping will send up to 100 000 packets and then exit with a failure status   unless it receives one reply packet  in which case it exits with a success status  The if will then execute the appropriate statement

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Here s my one-liner solution   screen -S internet-check -d -m -- bash -c  while   ping -c 1 google com  do echo -  done  echo Google responding to ping   mail -s internet-back my-email example com    This runs an infinite ping in a new screen session until there is a response  at which point it sends an e-mail to my-email example com  Useful in the age of e-mail sent to phones    You might want to check that mail is configured correctly by just running echo test   mail -s test my-email example com first  Of course you can do whatever you want from done  onwards  sound a bell  start a web browser  use your imagination

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I use this Bash script to test the internet status every minute on OSX   address 192 168 1 99    forced bad address for testing debugging address 23 208 224 170   www cisco com internet 1               default to internet is up  while true  do        a  Day of Week  textual        b  Month  textual  abbreviated        d  Day  numeric        r  Timestamp AM PM     echo -n   date    a   b  d   r    --        ping -c 1   address   gt   tmp ping       if       -ne 0     then         if      internet  -eq 1     then     edge trigger -- was up now down             echo -n   say  Internet down     OSX Text-to-Speech             echo -n  Internet DOWN          else             echo -n      still down          fi         internet 0     else         if      internet  -eq 0     then       edge trigger -- was down now up             echo -n   say  Internet back up     OSX Text-To-Speech         fi         internet 1     fi        cat  tmp ping     head -2   tail -1     sleep 60     sleep 60 seconds  1 min done

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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  lt sysexits h gt  if an error occurred    In other words  use something like     count   100                                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 to exit loop      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

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I liked paxdiablo s script  but wanted a version that ran indefinitely  This version runs ping until a connection is established and then prints a message saying so   echo  Testing      PING CMD  ping -t 3 -c 1 google com  gt   dev null 2 gt  amp 1   eval  PING CMD  if       -eq 0     then     echo  Already connected   else     echo -n  Waiting for connection          while true  do         eval  PING CMD          if       -eq 0     then             echo             echo Connected              break         else             sleep 0 5             echo -n           fi     done fi   I also have a Gist of this script which I ll update with fixes and improvements as needed

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This can also be done with a timeout     Ping until timeout or 1 successful packet ping -w  timeout  -c 1

[bash] Bash loop ping successful

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