这里有很多有趣的答案，但我从这个答案中获得了灵感，并将一个简单的脚本组合在一起，并行运行多个进程，并在完成后处理结果。你可以在以下要点中找到它:

#!/usr/bin/env bash

# inspired by https://stackoverflow.com/a/29535256/2860309

pids=""
failures=0

function my_process() {
    seconds_to_sleep=$1
    exit_code=$2
    sleep "$seconds_to_sleep"
    return "$exit_code"
}

(my_process 1 0) &
pid=$!
pids+=" ${pid}"
echo "${pid}: 1 second to success"

(my_process 1 1) &
pid=$!
pids+=" ${pid}"
echo "${pid}: 1 second to failure"

(my_process 2 0) &
pid=$!
pids+=" ${pid}"
echo "${pid}: 2 seconds to success"

(my_process 2 1) &
pid=$!
pids+=" ${pid}"
echo "${pid}: 2 seconds to failure"

echo "..."

for pid in $pids; do
        if wait "$pid"; then
                echo "Process $pid succeeded"
        else
                echo "Process $pid failed"
                failures=$((failures+1))
        fi
done

echo
echo "${failures} failures detected"

结果是:

86400: 1 second to success
86401: 1 second to failure
86402: 2 seconds to success
86404: 2 seconds to failure
...
Process 86400 succeeded
Process 86401 failed
Process 86402 succeeded
Process 86404 failed

2 failures detected

使用GNU Parallel http://www.gnu.org/software/parallel/，它就像:

(echo prog1; echo prog2) | parallel

或者如果你喜欢:

parallel ::: prog1 prog2

了解更多:

观看介绍视频快速介绍: https://www.youtube.com/playlist?list=PL284C9FF2488BC6D1 浏览教程(man parallel_tutorial)。您的命令行 会因此爱你的。 阅读:Ole Tange, GNU Parallel 2018 (Ole Tange, 2018)。

使用bashj (https://sourceforge.net/projects/bashj/)，您不仅可以运行多个进程(其他人建议的方式)，还可以在一个JVM中运行多个线程，这些线程由您的脚本控制。当然，这需要java JDK。线程比进程消耗更少的资源。

下面是一个工作代码:

#!/usr/bin/bashj

#!java

public static int cnt=0;

private static void loop() {u.p("java says cnt= "+(cnt++));u.sleep(1.0);}

public static void startThread()
{(new Thread(() ->  {while (true) {loop();}})).start();}

#!bashj

j.startThread()

while [ j.cnt -lt 4 ]
do
  echo "bash views cnt=" j.cnt
  sleep 0.5
done

你可以使用wait:

some_command &
P1=$!
other_command &
P2=$!
wait $P1 $P2

它将后台程序pid分配给变量($!是最后启动进程的PID)，然后wait命令等待它们。这很好，因为如果您终止了脚本，它也会终止进程!

xargs -P <n>允许并行运行<n个>命令。

虽然-P是一个非标准选项，但是GNU (Linux)和macOS/BSD实现都支持它。

示例如下:

最多同时运行3个命令， 只有在先前启动的进程终止时才启动附加命令。

time xargs -P 3 -I {} sh -c 'eval "$1"' - {} <<'EOF'
sleep 1; echo 1
sleep 2; echo 2
sleep 3; echo 3
echo 4
EOF

输出如下所示:

1   # output from 1st command 
4   # output from *last* command, which started as soon as the count dropped below 3
2   # output from 2nd command
3   # output from 3rd command

real    0m3.012s
user    0m0.011s
sys 0m0.008s

计时显示这些命令是并行运行的(最后一个命令仅在最初3个命令中的第一个命令终止后启动，但执行得非常快)。

xargs命令本身在所有命令完成之前不会返回，但是您可以在后台执行它，使用控制操作符&终止它，然后使用内置的wait等待整个xargs命令完成。

{
  xargs -P 3 -I {} sh -c 'eval "$1"' - {} <<'EOF'
sleep 1; echo 1
sleep 2; echo 2
sleep 3; echo 3
echo 4
EOF
} &

# Script execution continues here while `xargs` is running 
# in the background.
echo "Waiting for commands to finish..."

# Wait for `xargs` to finish, via special variable $!, which contains
# the PID of the most recently started background process.
wait $!

注意:

BSD/macOS xargs要求您显式地指定并行运行的命令的数量，而GNU xargs允许您指定-P 0以并行运行尽可能多的命令。 并行运行的进程的输出在生成时到达，因此它将不可预测地交错。 正如Ole的回答中所提到的(大多数平台都不是标准的)，GNU并行在每个进程的基础上方便地序列化(分组)输出，并提供了许多更高级的特性。

由于某些原因，我不能使用等待，我想出了这个解决方案:

# create a hashmap of the tasks name -> its command
declare -A tasks=(
  ["Sleep 3 seconds"]="sleep 3"
  ["Check network"]="ping imdb.com"
  ["List dir"]="ls -la"
)

# execute each task in the background, redirecting their output to a custom file descriptor
fd=10
for task in "${!tasks[@]}"; do
    script="${tasks[${task}]}"
    eval "exec $fd< <(${script} 2>&1 || (echo $task failed with exit code \${?}! && touch tasks_failed))"
    ((fd+=1))
done

# print the outputs of the tasks and wait for them to finish
fd=10
for task in "${!tasks[@]}"; do
    cat <&$fd
    ((fd+=1))
done

# determine the exit status
#   by checking whether the file "tasks_failed" has been created
if [ -e tasks_failed ]; then
    echo "Task(s) failed!"
    exit 1
else
    echo "All tasks finished without an error!"
    exit 0
fi