如何在bash脚本中等待从该脚本派生的几个子进程完成，然后在任何子进程以code !=0结束时返回退出代码!=0?
简单的脚本:
#!/bin/bash
for i in `seq 0 9`; do
doCalculations $i &
done
wait
上面的脚本将等待所有10个子进程，但它总是给出退出状态0(参见help wait)。我如何修改这个脚本，以便它将发现衍生子进程的退出状态，并在任何子进程以code !=0结束时返回退出代码1 ?
有没有比收集子进程的pid、按顺序等待它们并求和退出状态更好的解决方案呢?
当前回答
这是有效的，应该是一个很好的，如果不是更好的@HoverHell的答案!
#!/usr/bin/env bash
set -m # allow for job control
EXIT_CODE=0; # exit code of overall script
function foo() {
echo "CHLD exit code is $1"
echo "CHLD pid is $2"
echo $(jobs -l)
for job in `jobs -p`; do
echo "PID => ${job}"
wait ${job} || echo "At least one test failed with exit code => $?" ; EXIT_CODE=1
done
}
trap 'foo $? $$' CHLD
DIRN=$(dirname "$0");
commands=(
"{ echo "foo" && exit 4; }"
"{ echo "bar" && exit 3; }"
"{ echo "baz" && exit 5; }"
)
clen=`expr "${#commands[@]}" - 1` # get length of commands - 1
for i in `seq 0 "$clen"`; do
(echo "${commands[$i]}" | bash) & # run the command via bash in subshell
echo "$i ith command has been issued as a background job"
done
# wait for all to finish
wait;
echo "EXIT_CODE => $EXIT_CODE"
exit "$EXIT_CODE"
# end
当然，我已经在一个NPM项目中保存了这个脚本，它允许你并行运行bash命令，对测试很有用:
https://github.com/ORESoftware/generic-subshell
其他回答
这是有效的，应该是一个很好的，如果不是更好的@HoverHell的答案!
#!/usr/bin/env bash
set -m # allow for job control
EXIT_CODE=0; # exit code of overall script
function foo() {
echo "CHLD exit code is $1"
echo "CHLD pid is $2"
echo $(jobs -l)
for job in `jobs -p`; do
echo "PID => ${job}"
wait ${job} || echo "At least one test failed with exit code => $?" ; EXIT_CODE=1
done
}
trap 'foo $? $$' CHLD
DIRN=$(dirname "$0");
commands=(
"{ echo "foo" && exit 4; }"
"{ echo "bar" && exit 3; }"
"{ echo "baz" && exit 5; }"
)
clen=`expr "${#commands[@]}" - 1` # get length of commands - 1
for i in `seq 0 "$clen"`; do
(echo "${commands[$i]}" | bash) & # run the command via bash in subshell
echo "$i ith command has been issued as a background job"
done
# wait for all to finish
wait;
echo "EXIT_CODE => $EXIT_CODE"
exit "$EXIT_CODE"
# end
当然，我已经在一个NPM项目中保存了这个脚本，它允许你并行运行bash命令，对测试很有用:
https://github.com/ORESoftware/generic-subshell
我认为并行运行作业并检查状态的最直接方法是使用临时文件。已经有几个类似的答案(例如nietzsche -jou和mug896)。
#!/bin/bash
rm -f fail
for i in `seq 0 9`; do
doCalculations $i || touch fail &
done
wait
! [ -f fail ]
上面的代码不是线程安全的。如果你担心上面的代码会同时运行，最好使用一个更独特的文件名，比如fail.$$。最后一行是满足需求:“当任何子进程以code !=0结束时，返回退出代码1 ?”我又加了一条要求，要清理干净。这样写可能会更清楚:
#!/bin/bash
trap 'rm -f fail.$$' EXIT
for i in `seq 0 9`; do
doCalculations $i || touch fail.$$ &
done
wait
! [ -f fail.$$ ]
下面是一个类似的代码片段，用于从多个作业收集结果:我创建一个临时目录，在一个单独的文件中描述所有子任务的输出，然后转储它们以供查看。这和问题不太匹配——我把它作为奖励扔进去:
#!/bin/bash
trap 'rm -fr $WORK' EXIT
WORK=/tmp/$$.work
mkdir -p $WORK
cd $WORK
for i in `seq 0 9`; do
doCalculations $i >$i.result &
done
wait
grep $ * # display the results with filenames and contents
只需将结果存储在shell之外，例如在一个文件中。
#!/bin/bash
tmp=/tmp/results
: > $tmp #clean the file
for i in `seq 0 9`; do
(doCalculations $i; echo $i:$?>>$tmp)&
done #iterate
wait #wait until all ready
sort $tmp | grep -v ':0' #... handle as required
我想运行doCalculations;echo $ ?”>>/tmp/acc在一个子shell中被发送到后台，然后等待，然后/tmp/acc将包含退出状态，每行一个。不过，我不知道多个进程附加到累加器文件的任何后果。
下面是这个建议的一个例子:
文件:doCalcualtions
#!/bin/sh
random -e 20
sleep $?
random -e 10
文件:
#!/bin/sh
rm /tmp/acc
for i in $( seq 0 20 )
do
( ./doCalculations "$i"; echo "$?" >>/tmp/acc ) &
done
wait
cat /tmp/acc | fmt
rm /tmp/acc
running ./try的输出
5 1 9 6 8 1 2 0 9 6 5 9 6 0 0 4 9 5 5 9 8
我最近用过这个(感谢Alnitak):
#!/bin/bash
# activate child monitoring
set -o monitor
# locking subprocess
(while true; do sleep 0.001; done) &
pid=$!
# count, and kill when all done
c=0
function kill_on_count() {
# you could kill on whatever criterion you wish for
# I just counted to simulate bash's wait with no args
[ $c -eq 9 ] && kill $pid
c=$((c+1))
echo -n '.' # async feedback (but you don't know which one)
}
trap "kill_on_count" CHLD
function save_status() {
local i=$1;
local rc=$2;
# do whatever, and here you know which one stopped
# but remember, you're called from a subshell
# so vars have their values at fork time
}
# care must be taken not to spawn more than one child per loop
# e.g don't use `seq 0 9` here!
for i in {0..9}; do
(doCalculations $i; save_status $i $?) &
done
# wait for locking subprocess to be killed
wait $pid
echo
从这里，我们可以很容易地推断，并拥有一个触发器(触摸文件，发送信号)并改变计数标准(计数触摸的文件，或其他)以响应该触发器。或者如果你只是想要'any'非零rc，只需从save_status中杀死锁。
