Recursively renice

renice.sh

#!/bin/sh

PID_LIST=

platform='unknown'
unamestr=`uname`
if [[ "$unamestr" == 'Linux' ]]; then
    platform='linux'
    elif [[ "$unamestr" == 'FreeBSD' ]]; then
    platform='freebsd'
    elif [[ "$unamestr" == 'Darwin' ]]; then
    platform='freebsd'
fi


gnufindpids() {
    [ "$#" -eq 1 -a -d "/proc/$1/task" ] || exit 1
    for pid in /proc/$1/task/* ; do
        pid="$(basename "$pid")"
        PID_LIST="$PID_LIST$pid "
        for cpid in $(cat /proc/$1/task/$pid/children) ; do
            findpids $cpid
        done
    done
}
bsdfindpids() {
    pgrep -P $1
}

macfindpids() {
    if [ `which pstree` != 0 ]; then
        brew install pstree
    else
        echo "please install homebrew and or pstree"
    fi
    pstree -p $1 | awk -F' ' '{if(NR>1)print $2}'
}

if [[ $platform == 'Linux' ]]; then
    gnufindpids $1
    echo $PID_LIST
    elif [[ $platform == 'FreeBSD' ]]; then
    bsdfindpids $1
    echo $PID_LIST
    elif [[ $platform == 'Darwin' ]]; then
    macfindpids $1
    echo $PID_LIST
fi

# If process PID 1234 is the one you want to recursively nice, now you can do:
# renice -n 15 -p $(/path/to/findchildren.sh 1234)