timeout

run a commmand with a time limit

timeout [option] duration command [ args … ]

Start command, and kill it if still running after [ duration.

duration [seconds[s] | minutesm | daysd

--preserve-status Always exit with the status from command

--foreground when not running from a shell prompt, command reads from TTY and gets TTY signals; children of command will not be timed out

-k --kill-after=duration also send a KILL signal if command is still running this long after the initial signal was sent

-s
 --signal=signal

signal to be sent on timeout; signal may be a name like 'HUP' or a number.

 1) SIGHUP    2) SIGINT   3) SIGQUIT  4) SIGILL
 5) SIGTRAP  6) SIGABRT  7) SIGEMT   8) SIGFPE
 9) SIGKILL 10) SIGBUS  11) SIGSEGV 12) SIGSYS
13) SIGPIPE 14) SIGALRM 15) SIGTERM 16) SIGURG
17) SIGSTOP 18) SIGTSTP 19) SIGCONT 20) SIGCHLD
21) SIGTTIN 22) SIGTTOU 23) SIGIO   24) SIGXCPU
25) SIGXFSZ 26) SIGVTALRM   27) SIGPROF 28) SIGWINCH
29) SIGINFO 30) SIGUSR1 31) SIGUSR2

-v --verbose diagnose to stderr signals sent upon timeout

--help

--version

DURATION is a fixed point number with an optional suffix: 's' for seconds (the default), 'm' for minutes, 'h' for hours or 'd' for days. A duration of 0 disables the associated timeout.
If the command times out, and --preserve-status is not set, then exit with status 124. Otherwise, exit with the status of COMMAND. If no signal is specified, send the TERM signal upon timeout. The TERM signal kills any process that does not block or catch that signal. It may be necessary to use the KILL (9) signal, since this signal cannot be caught, in which case the exit status is 128+9 rather than 124. BUGS Some platforms don't currently support timeouts beyond the year 2038. GNU coreutils online help: Report any translation bugs to SEE ALSO kill(1) Full documentation or available locally via: info '(coreutils) timeout invocation'
/usr/bin/timeout utility is installed by default in most distros which is part of coreutils rpm in Linux Check if coreutils is installed on your server # rpm -q coreutils coreutils-8.22-24.el7.x86_64 We can use bash utility with timeout to test SSH connection by checking port 22 status. If you are using a different port for 22 then you can replace it in the below syntax Syntax: # timeout bash -c "/" Here server2 is my target host, I will execute the command with a timeout value of 5s on port 22 [root@server1 ~]# timeout 5 bash -c "