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如何为shell脚本引入超时？

tag-icon • tag-icon shell-script timeout
如何为shell脚本引入超时？

我想运行一个 shell 脚本，其中有一个循环，它可以永远运行，但我不希望发生这种情况。所以我需要为整个脚本引入一个超时。

如何在 SuSE 下为整个 shell 脚本引入超时？

答案1

如果 GNUtimeout不可用，您可以使用expect（Mac OS X、BSD...默认情况下通常没有 GNU 工具和实用程序）。

################################################################################
# Executes command with a timeout
# Params:
#   $1 timeout in seconds
#   $2 command
# Returns 1 if timed out 0 otherwise
timeout() {

    time=$1

    # start the command in a subshell to avoid problem with pipes
    # (spawn accepts one command)
    command="/bin/sh -c \"$2\""

    expect -c "set echo \"-noecho\"; set timeout $time; spawn -noecho $command; expect timeout { exit 1 } eof { exit 0 }"    

    if [ $? = 1 ] ; then
        echo "Timeout after ${time} seconds"
    fi

}

编辑 例子：

timeout 10 "ls ${HOME}"

答案2

谢谢你的澄清。

完成您的任务的最简单方法是使用包装器中的循环运行脚本，就像timeoutGNU Coreutils 包中的命令一样。

root@coraid-sp:~# timeout --help            
Usage: timeout [OPTION] DURATION COMMAND [ARG]...
   or: timeout [OPTION]
Start COMMAND, and kill it if still running after DURATION.

Mandatory arguments to long options are mandatory for short options too.
  -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
                   specify the signal to be sent on timeout.
                   SIGNAL may be a name like 'HUP' or a number.
                   See `kill -l` for a list of signals
      --help     display this help and exit
      --version  output version information and exit

DURATION is an integer with an optional suffix:
`s' for seconds(the default), `m' for minutes, `h' for hours or `d' for days.

If the command times out, 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.  For other processes, it may be necessary to
use the KILL (9) signal, since this signal cannot be caught.

Report timeout bugs to [email protected]
GNU coreutils home page: <http://www.gnu.org/software/coreutils/>
General help using GNU software: <http://www.gnu.org/gethelp/>
For complete documentation, run: info coreutils 'timeout invocation'

最后，这比编写自己的超时函数要容易得多，而 shell 往往没有内置超时函数。

答案3

从脚本中启动一个看门狗进程，以在运行时间过长时杀死其父进程。例子：

# watchdog process
mainpid=$$
(sleep 5; kill $mainpid) &
watchdogpid=$!

# rest of script
while :
do
   ...stuff...
done
kill $watchdogpid

该脚本将在五秒后被看门狗终止。

答案4

还有cratimeout作者：马丁·克拉考尔。

# cf. http://www.cons.org/cracauer/software.html
# usage: cratimeout timeout_in_msec cmd args
cratimeout 5000 sleep 600
cratimeout 5000 tail -f /dev/null
cratimeout 5000 sh -c 'while sleep 1; do date; done'

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