Thinking problem management!

#!/bin/bash # # usage updatethreatblock.sh <configuration file> # eg: updatethreatblock.sh /etc/ipset-threatblock/ipset-threatblock.conf # function exists() { command -v "$1" >/dev/null 2>&1 ; } if [[ -z "$1" ]]; then   echo "Error: please specify a configuration file, e.g. $0 /etc/ipset-threatblock/ipset-threatblock.conf"   exit 1 fi # shellcheck source=ipset-threatblock.conf if ! source "$1"; then   echo "Error: can't load configuration file $1"   exit 1 fi if ! exists curl && exists egrep && exists grep && exists ipset && exists iptables && exists sed && exists sort && exists wc ; then   echo >&2 "Error: searching PATH fails to find executables among: curl egrep grep ipset iptables sed sort wc"   exit 1 fi DO_OPTIMIZE_CIDR=no if exists iprange && [[ ${OPTIMIZE_CIDR:-yes} != no ]]; then   DO_OPTIMIZE_CIDR=yes fi if [[ ! -d $(dirname &q