Too Good To, UNIX & Linux

Too good to #0003

Linux uptime in seconds, once and for all

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awk '{printf "%i\n", $1}' /proc/uptime

“Sudo on demand”, re-exec shell script with sudo if not running as root

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#!/usr/bin/env bash
printf "Running as: %s\n" "$(id -un)"
[[ ${EUID} -ne 0 ]] && printf "Re-executing with sudo.\n" && exec sudo "${0}"

See also TGT0006, this is just as useful for downgrading privileges on the fly.

“When was the last time apt-get on that Debian/Ubuntu machine installed package upgrades?”

  • Reliably answering this is a lot harder than it looks, subject of countless discussions and really does need to parse /var/log/apt/history.log, which is painful.
  • The script below maintains a file /var/log/apt/lastupgrade with the last upgrade’s time stamp, for further processing.
  • Does NOT track invocations of apt-get upgrade that did not lead to package upgrades.
  • Does NOT look behind logfile rotations, which should not be a problem because it’s closely hooked to dpkg.

/usr/sbin/apt-lastupgrade:

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#!/bin/bash
 
while IFS=: read -r key value
do
    if [[ "${key}" == 'Start-Date' ]]
    then
        upgraded=0
    elif [[ "${key}" == 'Upgrade' ]]
    then
        upgraded=1
    elif [[ "${key}" == 'End-Date' ]]
    then
        if [[ ${upgraded} -eq 1 ]]
        then
            printf -v lastupgrade "%s" "${value}"
        fi
        upgraded=0
    fi
done < /var/log/apt/history.log
 
if [[ -v lastupgrade ]]
then
    tee /var/log/apt/lastupgrade <<-Here
    # Timestamp of last upgrade: ${lastupgrade}
    Here
    touch -d "${lastupgrade}" /var/log/apt/lastupgrade
fi

/etc/apt/apt.conf.d/90lastupgrade:

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DPkg::Post-Invoke {"/usr/bin/systemd-run --on-active=60 /usr/sbin/apt-lastupgrade || /bin/true"};

Path of running shell script, dirname for locating config files, includes etc.

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me_path="$(readlink -f "${0}")"
me_dir="$(dirname "${me_path}")"
me_base="$(basename "${me_path}")"