Looking for wisdom about Ubuntu¶

deactivate ‘caps lock’¶

https://kofler.info/desktop-konfiguration-fuer-ubuntu-18-04/

CapsLock deaktivieren

Die überflüssigste Taste jeder Tastatur ist CapsLock. Immer wieder führt ein unbeabsichtigtes Drücken zur eINGABE FEHLERHAFTEN tEXTS. Abhilfe: Im Programm Optimierungen (also Gnome Tweaks) gibt es im Dialogblatt Tastatur und Maus den merkwürdig beschrifteten Button Zusätzliche Belegungsoptionen. Er führt in einen Dialog, in dem Sie die Funktionen diverse Spezialtasten (Strg, Alt, Windows, CapsLock) verändern können. Dort gibt es auch die Möglichkeit, CapsLock ganz zu deaktivieren

system-monitor¶

| https://kofler.info/desktop-konfiguration-fuer-ubuntu-18-04/ | system-monitor - display system informations in gnome shell status bar, such as memory usage, cpu usage, network rates… |

Required:

sudo apt install gir1.2-gtop-2.0 gir1.2-networkmanager-1.0  gir1.2-clutter-1.0

Touchpad indicator¶

| https://extensions.gnome.org/extension/131/touchpad-indicator/ | https://kofler.info/desktop-konfiguration-fuer-ubuntu-18-04/ |

Increase password cache-time¶

Search

• https://www.startpage.com/do/dsearch?query=keep+gpg+password
• Keep GnuPG credentials cached for entire user session

Create ~/.gnupg/gpg-agent.conf

➜  ~ cat /home/marble/.gnupg/gpg-agent.conf

###+++--- GPGConf ---+++###
default-cache-ttl 28800
max-cache-ttl 288000
###+++--- GPGConf ---+++### Mi 27 Mai 2015 08:35:06 CEST
# GPGConf edited this configuration file.
# It will disable options before this marked block, but it will
# never change anything below these lines.
➜  ~

Restart gpg-agent

Usually you should not do this. But since we changed the config, let’s kill a running instance and wait until gpg-agents restarts automatically when needed with the new configuration:

gpgconf --kill gpg-agent

Integrate Sublime Text 3¶

1. Add Tool: Settings → Tools → External Tools

   Name: Sublime

   Group: External Editors

   Program: /usr/bin/subl

   Arguments: $FilePath$

   Working directory: $ProjectFileDir$

   Check: “Synchronize files after execution”

2. Add Keyboard shortcut:

   Settings → Keymap → External Tools → External Editors → Sublime:

   Add: Strg+Alt+X

Run PHP as module¶

# create new group htdocs
sudo groupadd htdocs
# add group 'htdocs' to user 'marble'
sudo usermod -a -G htdocs marble
# add group 'htdocs' to user 'www-data'
sudo usermod -a -G htdocs marble www-data
# logout and login again for memberships to take effect

# set user and group everywhere in 'htdocs'
sudo chown -R marble:htdocs /home/marble/htdocs
# make everything group writable
chmod -R g+w /home/marble/htdocs
# set group s bit for directories
find /home/marble/htdocs -type d -exec chmod g+s {} \;

# set umask for user
umask 002
echo "umask 002" >> ~/.zshrc

With etckeeper you may want to do:

sudo etckeeper vcs status
sudo etckeeper vcs commit "..."

Make Apache2 run with umask 002: https://serverfault.com/questions/383734/how-do-i-set-default-umask-in-apache-on-debian

To have the new umask running, check if the file /etc/apache2/envvars will be used within your Apache start file /etc/init.d/apache2:

…
PIDFILE=$(. /etc/apache2/envvars && echo $APACHE_PID_FILE)
…

Set your umask in /etc/apache2/envvars:

# umask 002 to create files with 0664 and folders with 0775
umask 002

Restart Apache2:

# pick on line of these:
sudo systemctl restart apache2
sudo systemctl restart apache2.service
sudo /etc/init.d/apache2 restart
sudo /usr/sbin/apachectl restart
# earlier
sudo service apache2 restart

Run a simple test PHP script:

<?php
if ($fp = fopen(time() . '.txt', 'w')) {
   fwrite($fp, 'This is a simple test.');
   fclose($fp);
   echo "done";
} else {
   echo "error - cannot create file";
}
?>

Check the difference:

ls -l *.txt
-rw-r--r--  1 www-data htdocs    22 Nov  9 13:24 1541766246.txt
-rw-rw-r--  1 www-data htdocs    22 Nov  9 13:24 1541766276.txt

Not enough file watches¶

Inotify Watches Limit: Read https://confluence.jetbrains.com/display/IDEADEV/Inotify+Watches+Limit

For an intelligent IDE, it is essential to be in the know about any external changes in files it is working with - e.g. changes made by VCS, or build tools, or code generators etc. For that reason, IntelliJ platform spins background process to monitor such changes. The method it uses is platform-specific, and on Linux, it is the Inotify facility.

Inotify requires a “watch handle” to be set for each directory in the project. Unfortunately, the default limit of watch handles may not be enough for reasonably sized projects, and reaching the limit will force IntelliJ platform to fall back to recursive scans of directory trees.

To prevent this situation it is recommended to increase the watches limit (to, say, 512K):

1. Add the following line to either /etc/sysctl.conf file or a new *.conf file (e.g. idea.conf) under /etc/sysctl.d/ directory:

   fs.inotify.max_user_watches = 524288
   

2. Then run this command to apply the change:

   sudo sysctl -p --system
   

   And don’t forget to restart your IDE.

   Note: the watches limit is per-account setting. If there are other programs running under the same account which also uses Inotify the limit should be raised high enough to suit needs of all of them.

No space left on device¶

Same as Not enough file watches.

Error

Failed to add /run/systemd/ask-password to directory watch: No space left on device

Solution

https://askubuntu.com/questions/828779/failed-to-add-run-systemd-ask-password-to-directory-watch-no-space-left-on-dev

Essence

• “To see what’s consuming inotify watches, use lsof:”

  sudo lsof -K | grep inotify | (less||more||pg)
  

• “The immediate fix is to run:”

  sudo -i
  echo 1048576 > /proc/sys/fs/inotify/max_user_watches
  exit
  

• “The long-term fix is to edit the file /etc/sysctl.conf to include the line:”

  fs.inotify.max_user_watches=1048576
  

php.ini¶

Old ‘brutal’ php.ini settings for a local dev purpose:

[Date]
date.timezone = 'Europe/Berlin'
[PHP]
display_errors = 'On'
display_startup_errors = 'On'
expose_php = 'On'
max_execution_time = '86400'
max_file_uploads = '20'
max_input_time = '600'
max_input_vars = '1500'
memory_limit = '2560M'
post_max_size = '50M'
upload_max_filesize = '50M'
[Pcre]
pcre.backtrack_limit = '1000000'
pcre.recursion_limit = '1000000'
[SQL]
sql.safe_mode = 'Off'
[mail function]
mail.add_x_header = 'On'
[xdebug]
xdebug.max_nesting_level=400
xdebug.remote_enable=1

Install for Linux¶

Follow the ‘apt’ method for Ubuntu/Debian: https://www.sublimetext.com/docs/3/linux_repositories.html

Choose the ‘dev’ sources.

# Install the GPG key:
wget -qO - https://download.sublimetext.com/sublimehq-pub.gpg | \
     sudo apt-key add -

## Ensure apt is set up to work with https sources:
## ((was not necessary for 18.04))
## sudo apt-get install apt-transport-https

## Stable
# echo "deb https://download.sublimetext.com/ apt/stable/" | \
        sudo tee /etc/apt/sources.list.d/sublime-text.list

# Dev
echo "deb https://download.sublimetext.com/ apt/dev/" | \
      sudo tee /etc/apt/sources.list.d/sublime-text.list

# Update apt sources and install Sublime Text
sudo apt update
sudo apt install sublime-text

Transfer Settings from old machine¶

Search the internet for “sublime copy settings”. Answer: Sync folder /home/marble/.config/sublime-text-3/Packages/User.

Guvcview¶

Good!

• https://wiki.ubuntuusers.de/guvcview/

• http://ubuntuhandbook.org/index.php/2018/10/guvcview-2-0-6-released-install-ubuntu/

• Install:

  sudo apt install guvcview
  

Installation¶

• Youtrack Jetbrains installation and upgrade

  Prerequisites

  To perform this installation, verify that the following prerequisites are met:

  You have installed Oracle Java SE Runtime Environment 8 or later. The instructions here require that the JRE is available from the path /usr/bin/java. Any external hostname (proxy hostname) is resolvable from the actual host where YouTrack is installed.

• https://linuxconfig.org/how-to-install-java-on-ubuntu-18-04-bionic-beaver-linux

  Install Java v11:

  # install java v11
  sudo add-apt-repository ppa:linuxuprising/java
  sudo apt update
  sudo synaptic
  sudo apt install oracle-java11-installer
  ➜  ~ java -version
  java version "11.0.1" 2018-10-16 LTS
  Java(TM) SE Runtime Environment 18.9 (build 11.0.1+13-LTS)
  Java HotSpot(TM) 64-Bit Server VM 18.9 (build 11.0.1+13-LTS, mixed mode)
  

  This installation of Java v11 works, but some Youtrack versions required an older Java. So let’s completely uninstall Java v11 and install Java v8 which does the job for Youtrack versions 6.5, 7, 2017.1, 2018.1, 2018.3 (= latest at the moment):

  # Install Java v8
  sudo add-apt-repository ppa:webupd8team/java
  sudo apt update
  sudo synaptic
  sudo apt install oracle-java11-installer
  ➜  ~ java -version
  java version "1.8.0_191"
  Java(TM) SE Runtime Environment (build 1.8.0_191-b12)
  Java HotSpot(TM) 64-Bit Server VM (build 25.191-b12, mixed mode)
  

How to copy the installation and upgrade to latest¶

New machine:

1. Install Java v8

2. We are using the ‘jar’-type installation and upgrading from 6.5

3. Download Youtrack JAR files for versions 7, 2017.1, 2018.1, 2018.3 (latest)

4. Create user ‘youtrack’

5. Copy OLD MACHINE /home/youtrack/teamsysdata to NEW MACHINE /home/youtrack/teamsysdata to

6. Upgrade step by step:

   New machine:

   • java -jar /home/youtrack/youtrack-7.jar 0.0.0.0:8112
   • java -jar /home/youtrack/youtrack-2017-1.jar 0.0.0.0:8112
   • java -jar /home/youtrack/youtrack-2018-1.jar 0.0.0.0:8112
   • java -jar /home/youtrack/youtrack-2018-3.jar 0.0.0.0:8112

Run as a service¶

• Install YouTrack JAR as service

  4. Create a systemd service file in the following directory: /etc/systemd/system/youtrack.service. Paste the following content into the youtrack.service file:

     [Unit]
     Description=Youtrack
     Requires=network.target
     After=syslog.target network.target
     
     [Service]
     Type=simple
     WorkingDirectory=/home/youtrack
     # ExecStart=/usr/bin/java -jar /home/youtrack/youtrack.jar --J-Xmx1G 8080
     ExecStart=/usr/bin/java -jar /home/youtrack/youtrack.jar --J-Xmx1G 0.0.0.0:8112
     User=youtrack
     
     [Install]
     WantedBy=default.target
     

     Customize the content of the file as needed: If you want YouTrack to start on a different port number, edit the default port 8080. Add and modify other Java parameters as needed.

     Use the following command to reload the systemd daemon and enable the YouTrack service on system start:

     systemctl daemon-reload
     systemctl enable youtrack.service
     

     Enter the following command to run the YouTrack service:

     service youtrack start
     

     Open http://<your-host-name>:8112 in a web browser and wait for the application to become available. As it takes some time to start the application, the port may be unreachable for a short while.

• We are running YouTrack on 0.0.0.0 and port 8112. This makes YouTrack available in our local network as youtrack.local.mbless.de:8112.

  Important: In the firewall open port 8112 on the new machine for incoming requests.

• Run netstat -tapn to verify that YouTrack is available.

Remove identity from key keeper¶

ssh-add -D   # Delete all identities (from key keeper)
ssh-add -D   # Delete identity       (from key keeper)
ssh-add -l   # List fingerprints of all identities
ssh-add --help

ssh-add -t 3600  # set lifetime for already stored keys to 1 hour