bash關機掛鉤;或者，殺死所有後臺進程，當主進程被殺死

Question

我有一個運行無盡的命令作爲後臺進程是bash：

#!/bin/bash 

function xyz() { 
    # some awk command 
} 

endlesscommand "param 1" | xyz & # async 
pids=$! 
endlesscommand "param 2" | xyz & # async 
pids="$pids "$! 
endlesscommand "param 3" | xyz # sync so the script doesn't leave 

停止該腳本的唯一方法是（必須）按Ctrl-C或殺滅和當發生這種情況時，我需要殺死$ pids變量中列出的所有後臺進程。 我該怎麼做？

如果有可能趕在主過程中的終止信號，這時執行功能（關閉掛鉤），我會做這樣的事情：

for $pid in $pids; do kill $pid; done; 

但我找不到如何從以下職位做到這一點...

---

SOLUTION：

#!/bin/bash 

function xyz() { 
# some awk command 
} 

trap 'jobs -p | xargs kill' EXIT # part of the solution 

endlesscommand "param 1" | xyz & # async 
endlesscommand "param 2" | xyz & # async 
endlesscommand "param 3" | xyz & # don't sync, but wait: 

# other part of the solution: 
while pgrep -P "$BASHPID" > /dev/null; do 
    wait 
done 

Answer 1

下面是一個不需要你跟蹤pids陷阱的父進程：

trap 'jobs -p | xargs kill' EXIT 

編輯：@Barmar問這可以在通常不可用的作業控制非源腳本內工作。它的確如此。考慮一下這個腳本：

$ cat no-job-control 
#! /bin/bash 

set -e -o pipefail 

# Prove job control is off 
if suspend 
then 
    echo suspended 
else 
    echo suspension failed, job control must be off 
fi 

echo 

# Set up the trap 
trap 'jobs -p | xargs kill' EXIT 

# Make some work 
(echo '=> Starting 0'; sleep 5; echo '=> Finishing 0') & 
(echo '=> Starting 1'; sleep 5; echo '=> Finishing 1') & 
(echo '=> Starting 2'; sleep 5; echo '=> Finishing 2') & 

echo "What's in jobs -p?" 
echo 

jobs -p 

echo 
echo "Ok, exiting now" 
echo 

在運行的時候，我們看到三個組長的PID，然後看到他們殺：

$ ./no-job-control 
./no-job-control: line 6: suspend: cannot suspend: no job control 
suspension failed, job control must be off 

=> Starting 0 
What's in jobs -p? 
=> Starting 1 

54098 
54099 
54100 

Ok, exiting now 

=> Starting 2 
./no-job-control: line 31: 54098 Terminated: 15   (echo '=> Starting 0'; sleep 5; echo '=> Finishing 0') 
./no-job-control: line 31: 54099 Terminated: 15   (echo '=> Starting 1'; sleep 5; echo '=> Finishing 1') 
./no-job-control: line 31: 54100 Terminated: 15   (echo '=> Starting 2'; sleep 5; echo '=> Finishing 2') 

如果我們不是註釋掉trap線並重新運行時，三個工作不會消失，實際上幾秒鐘後就會打印出他們的最終消息。注意返回的提示與最終輸出交錯。

$ ./no-job-control 
./no-job-control: line 6: suspend: cannot suspend: no job control 
suspension failed, job control must be off 

=> Starting 0 
What's in jobs -p? 

54110 
54111 
54112 
=> Starting 1 

Ok, exiting now 

=> Starting 2 
$ => Finishing 0 
=> Finishing 2 
=> Finishing 1 

Answer 2

kill `ps axl | grep "endlesscommand" | awk '{printf $4" "}'` 

這將尋找那些被影響「endlesscommand」

Answer 3

你可以使用pgrep和一個函數來殺死在主進程下創建的所有進程，像這樣。這不僅會殺死直接的子進程，而且還會殺死直接子進程。

#!/bin/bash 

function killchildren { 
    local LIST=() IFS=$'\n' A 
    read -a LIST -d '' < <(exec pgrep -P "$1") 
    local A SIGNAL="${2:-SIGTERM}" 
    for A in "${LIST[@]}"; do 
     killchildren_ "$A" "$SIGNAL" 
    done 
} 

function killchildren_ { 
    local LIST=() 
    read -a LIST -d '' < <(exec pgrep -P "$1") 
    kill -s "$2" "$1" 
    if [[ ${#LIST[@]} -gt 0 ]]; then 
     local A 
     for A in "${LIST[@]}"; do 
      killchildren_ "$A" "$2" 
     done 
    fi 
} 

trap 'killchildren "$BASHPID"' EXIT 

endlesscommand "param 1" & 
endlesscommand "param 2" & 
endlesscommand "param 3" & 

while pgrep -P "$BASHPID" >/dev/null; do 
    wait 
done 

至於你的原代碼，這將是最好只使用數組，你也不需要使用一個for循環：

#!/bin/bash 

trap 'kill "${pids[@]}"' EXIT 

pids=() 
endlesscommand "param 1" & # async 
pids+=("$!") 
endlesscommand "param 2" & # async 
pids+=("$!") 
endlesscommand "param 3" & # syncing this is not a good idea since if the main process would end along with it if it ends earlier. 
pids+=("$!") 

while pgrep -P "$BASHPID" >/dev/null; do 
    wait 
done 

原函數參考：http://www.linuxquestions.org/questions/blog/konsolebox-210384/bash-functions-to-list-and-kill-or-send-signals-to-process-trees-34624/