Fast Pacman Update Checker for bash/zsh

Mic92 · 2013-05-09 08:17:52

I saw some fancy notifiers using Desktop Notification or the systray on this forum, but nothing suitable for my arch server.
The following snippet check for updates once a day, whenever you spawn a new shell.

#!/bin/bash
# add this to your bashrc/zshrc
function _current_epoch {
  echo "$(($(date +%s) / 60 / 60 / 24))"
}

function _check_updates {
  (
    flock -n 9 || return # one concurrent update process at the time
    local ignored_pkgs="^linux"
    #local updates=`wc -l < /var/log/pacman-updates.log`
    local updates=`grep -Ev $ignored_pkgs /var/log/pacman-updates.log | wc -l`
    if [ $updates -gt 0 ]; then
      echo -n "There are $updates updates. Upgrade? (y/n) [n] "
      read line
      if [ "$line" = Y ] || [ "$line" = y ]; then
        yaourt -Syu --aur
        pacman -Qu | sudo tee /var/log/pacman-updates.log >/dev/null
      fi
    fi
    echo "$(_current_epoch)" > $HOME/.pacman-update
  ) 9> ~/.pacman-update.lck
}

if [[ $- == *i* ]] && # only interactive shells
  [ -e /var/log/pacman-updates.log ] && # only after first update
  [ ! -e /var/lib/pacman/db.lck ]; then # not if pacman is running
  if [ -e .pacman-update ]; then
    read last_epoch < $HOME/.pacman-update
    if [[ -n "$last_epoch" ]]; then
      if [ $(($(_current_epoch) - $last_epoch)) -ge 1 ]; then
        _check_updates
      fi
    fi
    unset last_epoch
  else
    _check_updates
  fi
fi

To keep my package cache up to date I use a systemd.timer unit.
It prefetchs all new packages without installing them or touching the database

#/etc/systemd/timer-daily.timer
[Unit]                                                                                                                                                
Description=Daily Timer                                                                                                                               
                                                                                                                                                      
[Timer]                                                                                                                                               
OnBootSec=10min                                                                                                                                       
OnUnitActiveSec=1d                                                                                                                                    
Unit=timer-daily.target                                                                                                                               
                                                                                                                                                      
[Install]                                                                                                                                             
WantedBy=basic.target

#/etc/systemd/timer-daily.target
[Unit]                                                                                                                                                
Description=Daily Timer Target                                                                                                                        
StopWhenUnneeded=yes

#/etc/systemd/timer-daily.target.wants/pacman-update.service 
[Unit]
Description=Update pacman's package cache

[Service]
Type=oneshot
Nice=19
IOSchedulingClass=2
IOSchedulingPriority=7
Environment=CHECKUPDATE_DB=/var/lib/pacman/checkupdate                                                                                                
ExecStartPre=/bin/sh -c "/usr/bin/checkupdates > /var/log/pacman-updates.log"                                                                         
ExecStart=/usr/bin/pacman --sync --upgrades --downloadonly --noconfirm --dbpath=/var/lib/pacman/checkupdate

Have fun.

UPDATE
Use the safer checkupdates script, so it will not touch the sync database, which prevents dangerous partial system upgrades

UPDATE 2
Do not check for updates if pacman is running. Use Type=oneshot to prevent timeout.

Last edited by Mic92 (2013-07-20 05:04:33)

Pierre · 2013-05-09 08:48:57

Running -Sy automatically is quite bad. Instead replace all this with the "checkupdates" command that already comes with pacman.

DaveCode · 2013-05-09 23:22:39

Thank you Mic92, I appreciate this effort. Pacman needs more control options. Automatic update is an area for work though some may think otherwise. My experience is that logging pacnew files with nightly or weekly auto-reboot keeps auto-updates running fine. I inspect pacnew files by remote SSH once a month.

Pierre, what command line(s) did you mean by "checkupdates"?

Allan · 2013-05-09 23:51:51

DaveCode wrote:

Pierre, what command line(s) did you mean by "checkupdates"?

Run "checkupdates"... It is a script provided by pacman.

Mic92 · 2013-05-10 15:50:42

Pierre wrote:

Running -Sy automatically is quite bad. Instead replace all this with the "checkupdates" command that already comes with pacman.

What are the possible consequence of just using pacman -Syuw.
As far a as I understand it only updates my local package database and download the packages?

karol · 2013-05-10 16:20:17

The problem is that it doesn't install the packages in question (but unsupervised - i.e. '--noconfirm' updating - is a bad idea too). If you now run 'pacman -S foo' without performing a proper full system update first, it can lead to breakage: https://bbs.archlinux.org/viewtopic.php?id=89328

Mic92 · 2013-05-11 11:20:45

I replaced pacman -Sy with checkupdates. I assume it is save to update just the package cache without alternating the database, isn't it?

karol · 2013-05-11 11:27:04

Yes, checkupdates uses a temporary database.

DaveCode · 2013-05-14 08:35:37

Tip, look into pacaur philosophy.

Shell helpers seem strange to mix with automation. My habit at shell is to enter pacaur -Syu and say no to the updates unless/until I want what I see, or the update list gets big. In that case I plan a restaurant break to coincide with my manual update.

Autoupdates can run at a particular time like early AM before working hours, when nightowls finally sleep but before morning office rush.

Arch Linux

#1 2013-05-09 08:17:52

Fast Pacman Update Checker for bash/zsh

#2 2013-05-09 08:48:57

Re: Fast Pacman Update Checker for bash/zsh

#3 2013-05-09 23:22:39

Re: Fast Pacman Update Checker for bash/zsh

#4 2013-05-09 23:51:51

Re: Fast Pacman Update Checker for bash/zsh

#5 2013-05-10 15:50:42

Re: Fast Pacman Update Checker for bash/zsh

#6 2013-05-10 16:20:17

Re: Fast Pacman Update Checker for bash/zsh

#7 2013-05-11 11:20:45

Re: Fast Pacman Update Checker for bash/zsh

#8 2013-05-11 11:27:04

Re: Fast Pacman Update Checker for bash/zsh

#9 2013-05-14 08:35:37

Re: Fast Pacman Update Checker for bash/zsh

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