为了将此并行化…

for i in $(whatever_list) ; do
   do_something $i
done

翻译成这样…

for i in $(whatever_list) ; do echo $i ; done | ## execute in parallel...
   (
   export -f do_something ## export functions (if needed)
   export PATH ## export any variables that are required
   xargs -I{} --max-procs 0 bash -c ' ## process in batches...
      {
      echo "processing {}" ## optional
      do_something {}
      }' 
   )

If an error occurs in one process, it won't interrupt the other processes, but it will result in a non-zero exit code from the sequence as a whole. Exporting functions and variables may or may not be necessary, in any particular case. You can set --max-procs based on how much parallelism you want (0 means "all at once"). GNU Parallel offers some additional features when used in place of xargs -- but it isn't always installed by default. The for loop isn't strictly necessary in this example since echo $i is basically just regenerating the output of $(whatever_list). I just think the use of the for keyword makes it a little easier to see what is going on. Bash string handling can be confusing -- I have found that using single quotes works best for wrapping non-trivial scripts. You can easily interrupt the entire operation (using ^C or similar), unlike the the more direct approach to Bash parallelism.

下面是一个简化的工作示例……

for i in {0..5} ; do echo $i ; done |xargs -I{} --max-procs 2 bash -c '
   {
   echo sleep {}
   sleep 2s
   }'

这是我使用的东西:

#wait for jobs
for job in `jobs -p`; do wait ${job}; done

http://jeremy.zawodny.com/blog/archives/010717.html:

#!/bin/bash

FAIL=0

echo "starting"

./sleeper 2 0 &
./sleeper 2 1 &
./sleeper 3 0 &
./sleeper 2 0 &

for job in `jobs -p`
do
echo $job
    wait $job || let "FAIL+=1"
done

echo $FAIL

if [ "$FAIL" == "0" ];
then
echo "YAY!"
else
echo "FAIL! ($FAIL)"
fi

简单地说:

#!/bin/bash

pids=""

for i in `seq 0 9`; do
   doCalculations $i &
   pids="$pids $!"
done

wait $pids

...code continued here ...

更新:

正如许多评论者指出的那样，上面的代码在继续之前会等待所有进程完成，但如果其中一个进程失败了，它不会退出，也不会失败，可以通过@Bryan， @SamBrightman和其他人建议的以下修改来完成:

#!/bin/bash

pids=""
RESULT=0


for i in `seq 0 9`; do
   doCalculations $i &
   pids="$pids $!"
done

for pid in $pids; do
    wait $pid || let "RESULT=1"
done

if [ "$RESULT" == "1" ];
    then
       exit 1
fi

...code continued here ...

我不相信Bash的内置功能可以做到这一点。

你可以在child退出时得到通知:

#!/bin/sh
set -o monitor        # enable script job control
trap 'echo "child died"' CHLD

然而，在信号处理程序中没有明显的方法来获取子进程的退出状态。

获得子状态通常是底层POSIX api中的等待函数族的工作。不幸的是，Bash对此的支持是有限的——您可以等待一个特定的子进程(并获得其退出状态)，也可以等待所有子进程，但总是得到0结果。

似乎不可能做到的是waitpid(-1)的等效，它会阻塞直到任何子进程返回。

在等待流程之前，流程可能已经完成。如果我们触发等待一个已经完成的进程，它将触发一个错误，比如pid不是这个shell的子进程。为了避免这种情况，可以使用以下函数来查找过程是否完成:

isProcessComplete(){
PID=$1
while [ -e /proc/$PID ]
do
    echo "Process: $PID is still running"
    sleep 5
done
echo "Process $PID has finished"
}