squid-reload

#!/bin/sh

CONFIG="/etc/squid/squid.second-instance.conf"

export PATH="$PATH:/usr/sbin"  # ..needed under Cron

Wait_listen()     { for n in `seq 1 30`; do ss -ntl "sport = :$1" | grep -q ^LISTEN && return 0; sleep 1; done; echo "Timeout: wait_listen $1"    ; return 1; }
Wait_not_listen() { for n in `seq 1 30`; do ss -ntl "sport = :$1" | grep -q ^LISTEN || return 0; sleep 1; done; echo "Timeout: wait_not_listen $1"; return 1; }

echo "Try to start second Squid..."
if test -s "$CONFIG" && squid -f "$CONFIG" && Wait_listen "4130" && sleep 15; then
    echo "Redirect firewall to second Squid..."
    iptables-save | awk '/^-A PREROUTING .* 3129$/ { $1=$NF=""; print "iptables -t nat -I", $0, "4129"; exit }' | sh -
    iptables-save | awk '/^-A PREROUTING .* 3130$/ { $1=$NF=""; print "iptables -t nat -I", $0, "4130"; exit }' | sh -
fi

echo "Reconfigure main Squid..."
squid -k reconfigure

Wait_not_listen 3130
Wait_listen     3130

test  -s /var/run/squid/squid2.pid && echo "Kill second squid..." && sleep 15
pkill -F /var/run/squid/squid2.pid

iptables-save | awk '/^-A PREROUTING .* 4129$/ { $1="";  print "iptables -t nat -D", $0; exit }' | sh -
iptables-save | awk '/^-A PREROUTING .* 4130$/ { $1="";  print "iptables -t nat -D", $0; exit }' | sh -

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