How to complete a script process tree in Cygwin bash from a bash script

Question

I have a Cygwin bash script that I need to watch and complete under certain conditions - in particular, after creating a specific file. It’s hard for me to figure out exactly how to finish the script with the same level of completeness as Ctrl + C.

Here's a simple script (called ) that does a little more than wait for completion. test1

#!/bin/bash

test -f kill_me && rm kill_me

touch kill_me
tail -f kill_me

If this script is run in the foreground, Ctrl + C will interrupt both the tailscript and the script. If the script is running in the background, kill %1(assuming that this task 1) will also complete both tail, and the script.

However, when I try to do the same thing from a script, I find that only the bashprocess that runs the script terminates and tailhangs around disconnected from its parent. Here is one of the ways I tried ( test2):

#!/bin/bash

test -f kill_me && rm kill_me

(
    touch kill_me
    tail -f kill_me
) &

while true; do
    sleep 1
    test -f kill_me && {
        kill %1
        exit
    }
done

If this is done, the bash sub-element running in the background completes OK, but tailstill hangs around.

If I use an explicitly allocated script like this, it still doesn't work ( test3):

#!/bin/bash

test -f kill_me && rm kill_me

# assuming test1 above is included in the same directory
./test1 &

while true; do
    sleep 1
    test -f kill_me && {
        kill %1
        exit
    }
done

tail still hanging after this script.

, ; , , , , , . , killall , , .

Answer 1

/bin/kill (, bash) PID " ", .

kill %1

/bin/kill -- -$$

.

Answer 2

, , - .

script Cygwin, . :

#!/bin/bash

function usage
{
    echo "usage: $(basename $0) [-c] [-<sigspec>] <pid>..."
    echo "Recursively kill the process tree(s) rooted by <pid>."
    echo "Options:"
    echo "  -c        Only kill children; don't kill root"
    echo "  <sigspec> Arbitrary argument to pass to kill, expected to be signal specification"
    exit 1
}

kill_parent=1
sig_spec=-9

function do_kill # <pid>...
{
    kill "$sig_spec" "$@"
}

function kill_children # pid
{
    local target=$1
    local pid=
    local ppid=
    local i
    # Returns alternating ids: first is pid, second is parent
    for i in $(ps -f | tail +2 | cut -b 10-24); do
        if [ ! -n "$pid" ]; then
            # first in pair
            pid=$i
        else
            # second in pair
            ppid=$i
            (( ppid == target && pid != $$ )) && {
                kill_children $pid
                do_kill $pid
            }
            # reset pid for next pair
            pid=
        fi
    done

}

test -n "$1" || usage

while [ -n "$1" ]; do
    case "$1" in
        -c)
            kill_parent=0
            ;;

        -*)
            sig_spec="$1"
            ;;

        *)
            kill_children $1
            (( kill_parent )) && do_kill $1
            ;;
    esac
    shift
done

, bash , , "", "" "" ( , ). , .

Answer 3

This script looks like this:

#!/bin/bash
# Author: Sunil Alankar

##
# recursive kill. kills the process tree down from the specified pid
#

# foreach child of pid, recursive call dokill
dokill() {
    local pid=$1
    local itsparent=""
    local aprocess=""
    local x=""
    # next line is a single line
    for x in `/bin/ps -f | sed -e '/UID/d;s/[a-zA-Z0-9_-]\{1,\}
\{1,\}\([0-9]\{1,\}\) \{1,\}\([0-9]\{1,\}\) .*/\1 \2/g'`
    do
        if [ "$aprocess" = "" ]; then
            aprocess=$x
            itsparent=""
            continue
        else
            itsparent=$x
            if [ "$itsparent" = "$pid" ]; then
                dokill $aprocess
            fi
            aprocess=""
        fi
    done
    echo "killing $1"
    kill -9 $1 > /dev/null 2>&1
}

case $# in
1) PID=$1
        ;;
*) echo "usage: rekill <top pid to kill>";
        exit 1;
        ;;
esac

dokill $PID