这回答命令行命令自动杀死一个命令后,一定的时间
建议使用1行方法使bash命令行中运行的命令超时:
( /path/to/slow command with options ) & sleep 5 ; kill $!
但是,给定的“长时间运行”命令可能会在超时之前完成。
(让我们称它为“通常运行时间长但有时很快”的命令,或者简称为tlrbsf。)
所以这个漂亮的一行方法有几个问题。
首先,睡眠不是有条件的,因此在序列完成所花费的时间上设置了一个不希望的下界。当tlrbsf命令在2秒内完成时,考虑30秒或2m甚至5m的睡眠时间——这是非常不可取的。
其次,kill是无条件的,因此该序列将尝试kill一个未运行的进程并抱怨它。
所以…
是否有一种方法可以超时一个典型的长时间运行但有时快速(“tlrbsf”)命令
有一个bash实现(另一个问题已经有Perl和C的答案)
将终止在较早的两个:TLRBSF程序终止,或超时过去
不会杀死不存在/不运行的进程(或者,可选:不会抱怨失败的杀死)
不一定非要是一行字
可以在Cygwin或Linux下运行吗
... 还有,为了加分
在前台运行TLRBSF命令
任何“睡眠”或额外的进程在后台
这样,TLRBSF命令的stdin/stdout/stderr可以重定向,就像它已经直接运行吗?
如果是,请分享你的代码。如果不是,请解释原因。
我花了一段时间试图破解前面提到的例子,但我的bash技能达到了极限。
我提出了一个问题,以保留shell上下文和允许超时,唯一的问题是它将停止脚本执行超时-但这是我提出的需求很好:
#!/usr/bin/env bash
safe_kill()
{
ps aux | grep -v grep | grep $1 >/dev/null && kill ${2:-} $1
}
my_timeout()
{
typeset _my_timeout _waiter_pid _return
_my_timeout=$1
echo "Timeout($_my_timeout) running: $*"
shift
(
trap "return 0" USR1
sleep $_my_timeout
echo "Timeout($_my_timeout) reached for: $*"
safe_kill $$
) &
_waiter_pid=$!
"$@" || _return=$?
safe_kill $_waiter_pid -USR1
echo "Timeout($_my_timeout) ran: $*"
return ${_return:-0}
}
my_timeout 3 cd scripts
my_timeout 3 pwd
my_timeout 3 true && echo true || echo false
my_timeout 3 false && echo true || echo false
my_timeout 3 sleep 10
my_timeout 3 pwd
输出:
Timeout(3) running: 3 cd scripts
Timeout(3) ran: cd scripts
Timeout(3) running: 3 pwd
/home/mpapis/projects/rvm/rvm/scripts
Timeout(3) ran: pwd
Timeout(3) running: 3 true
Timeout(3) ran: true
true
Timeout(3) running: 3 false
Timeout(3) ran: false
false
Timeout(3) running: 3 sleep 10
Timeout(3) reached for: sleep 10
Terminated
当然,我认为有一个目录叫做脚本
我认为这正是你所要求的:
http://www.bashcookbook.com/bashinfo/source/bash-4.0/examples/scripts/timeout3
#!/bin/bash
#
# The Bash shell script executes a command with a time-out.
# Upon time-out expiration SIGTERM (15) is sent to the process. If the signal
# is blocked, then the subsequent SIGKILL (9) terminates it.
#
# Based on the Bash documentation example.
# Hello Chet,
# please find attached a "little easier" :-) to comprehend
# time-out example. If you find it suitable, feel free to include
# anywhere: the very same logic as in the original examples/scripts, a
# little more transparent implementation to my taste.
#
# Dmitry V Golovashkin <Dmitry.Golovashkin@sas.com>
scriptName="${0##*/}"
declare -i DEFAULT_TIMEOUT=9
declare -i DEFAULT_INTERVAL=1
declare -i DEFAULT_DELAY=1
# Timeout.
declare -i timeout=DEFAULT_TIMEOUT
# Interval between checks if the process is still alive.
declare -i interval=DEFAULT_INTERVAL
# Delay between posting the SIGTERM signal and destroying the process by SIGKILL.
declare -i delay=DEFAULT_DELAY
function printUsage() {
cat <<EOF
Synopsis
$scriptName [-t timeout] [-i interval] [-d delay] command
Execute a command with a time-out.
Upon time-out expiration SIGTERM (15) is sent to the process. If SIGTERM
signal is blocked, then the subsequent SIGKILL (9) terminates it.
-t timeout
Number of seconds to wait for command completion.
Default value: $DEFAULT_TIMEOUT seconds.
-i interval
Interval between checks if the process is still alive.
Positive integer, default value: $DEFAULT_INTERVAL seconds.
-d delay
Delay between posting the SIGTERM signal and destroying the
process by SIGKILL. Default value: $DEFAULT_DELAY seconds.
As of today, Bash does not support floating point arithmetic (sleep does),
therefore all delay/time values must be integers.
EOF
}
# Options.
while getopts ":t:i:d:" option; do
case "$option" in
t) timeout=$OPTARG ;;
i) interval=$OPTARG ;;
d) delay=$OPTARG ;;
*) printUsage; exit 1 ;;
esac
done
shift $((OPTIND - 1))
# $# should be at least 1 (the command to execute), however it may be strictly
# greater than 1 if the command itself has options.
if (($# == 0 || interval <= 0)); then
printUsage
exit 1
fi
# kill -0 pid Exit code indicates if a signal may be sent to $pid process.
(
((t = timeout))
while ((t > 0)); do
sleep $interval
kill -0 $$ || exit 0
((t -= interval))
done
# Be nice, post SIGTERM first.
# The 'exit 0' below will be executed if any preceeding command fails.
kill -s SIGTERM $$ && kill -0 $$ || exit 0
sleep $delay
kill -s SIGKILL $$
) 2> /dev/null &
exec "$@"