2021-11-25 23:26:17 +00:00
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#!/usr/bin/env bash
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# Usage:
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# configLine [searchPattern] [replaceLine] [filePath]
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# Ref https://stackoverflow.com/a/54909102/1460422
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config_line() {
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2021-12-26 14:59:12 +00:00
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local OLD_LINE_PATTERN NEW_LINE NEW FILE
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OLD_LINE_PATTERN="$1"; shift
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NEW_LINE="$1"; shift
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FILE="$1"
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NEW="$(echo "${NEW_LINE}" | sed 's/\//\\\//g')";
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2021-11-25 23:26:17 +00:00
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touch "${FILE}"
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sed -i '/'"${OLD_LINE_PATTERN}"'/{s/.*/'"${NEW}"'/;h};${x;/./{x;q100};x}' "${FILE}"
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if [[ $? -ne 100 ]] && [[ ${NEW_LINE} != '' ]]
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then
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echo "${NEW_LINE}" >> "${FILE}"
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fi
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}
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log_msg() {
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2021-11-26 22:31:14 +00:00
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echo -e "[ ${HOSTNAME} ] [ $(date -u +"%Y-%m-%dT%H:%M:%SZ") ] $*" >&2;
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2021-11-25 23:26:17 +00:00
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}
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# Old approach - we've learned we can override /etc/network/interfaces via /etc/dhcp/dhclient.conf
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# config_line "dns-nameservers" "dns-nameservers 172.16.230.100" "/etc/network/interfaces";
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completed_file="/etc/dhcp/sbrl-dns-configured";
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log_msg "Configuring DNS nameserver";
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if [[ ! -f "${completed_file}" ]]; then
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log_msg "DNS nameserver not yet configured, appending to /etc/dhcp/dhclient.conf";
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echo "interface \"eth0\" {
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supersede domain-name-servers 172.16.230.100;
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}" | sudo tee -a /etc/dhcp/dhclient.conf;
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sudo touch "${completed_file}";
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log_msg "Complete, this machine needs a reboot to activate the new config directives";
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else
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log_msg "DNS nameserver config written already, no changes made";
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fi
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