1
vote
2answers
2k views

What is the difference between ping -w and ping -W?

What is the -w (deadline) flag in ping for? I cannot find a description of it in the ping man page; only for -W, which takes seconds as a parameter. What is the difference between them, and how can I ...
1
vote
2answers
302 views

need portable crontab host-checking/failover logic across Linux & Cygwin

A host-ping test that always works correctly from the interactive bash command line in Cygwin, is behaving incorrectly in its own crontab--always selecting the second host--and I can't figure out why: ...
4
votes
4answers
2k views

“internet connection checker one-liner”

With this I can check, that there is "internet connection". if there is no "internet connection" (succesfull pings to this 2 places), then it waits 600 sec, then it runs along: ping -W 1 -c 4 ...
4
votes
3answers
5k views

How can i check that a remote computer is online for ssh / script acess?

i'm writting a script that will backup data from my laptop to an ubuntu server. to do so, i'm looking for a (ba)sh command to test if the server is available before starting the backup. something like ...