Linux

Working with certificates in Java This post contains a mix of java and certificate info. Note that you should definitely use the p12 format in Java. Using other types, like p8, usually end up causing issues in the end. One easy way is by creating a custom trust manager The easiest way of doing this is: (See this link for a code example on stackoverflow Create a custom trust manager with your special certs Create a trust manager with the default certs Create a custom trust manager, which takes the custom and the default trust manager and try them both Another way of doing it would be adding the certificate manually to the cacerts file. Note that you will either need the full certificate chain for it to work, or just the root cert might also work. Note that certs added to the java key store must be in DER-format. See below for converting between formats. When adding with the keytool, you will either need to specify the path manually, or add it with the -cacerts flag to add it to the main key store. The keystore will ask you for password, but the password usually is changeit ...

Sometimes when you exec into a docker container normally, the size of the containers terminal will be much smaller than your real screen, making it not work properly. To solve this you need to set COLUMNS and LINES in the containers env: sudo docker exec -e COLUMNS="$(tput cols)" -e LINES="$(tput lines)" -it docker-container bash

If you are using firefox on linux with a dark theme, unstyled input fields will have black background and white text. Sometimes just white text on white background. According to this bug report it has been this way for the last 17 years. To fix it, pop by about:config and add a new key-value (String): "widget.content.gtk-theme-override": "Adwaita:light". After restarting firefox, things will be as they should be.

So maybe sounds like crap is an overstatement, but compared to what it sounds like on windows / macos / my phone it’s not even a comparison. Apparently this is is caused by the pulseaudio-profile being set wrong. You can check available profiles by connecting to the bluetooth headphones and running pacmd list: profiles: headset_head_unit: Headset Head Unit (HSP/HFP) (priority 20, available: unknown) a2dp_sink: High Fidelity Playback (A2DP Sink) (priority 10, available: no) off: Off (priority 0, available: yes) When trying to set the profile, pacmd will refused (related to the available: no): ...

I recently decided to dual boot linux my macbook air from 2014 (or maybe 2015). Apparently dual booting on macOS works really well, since you will enter GRUB on normal boots, but can enter macOS by holding the alt/option key during boot. However, there are no free wifi drivers available, so you will need to download extra non-free drivers, which can be really annoying if you only have wifi to connect by, and wifi doesn’t work. ...

Sometimes your install a distro and it refuses to take up all available space. 1. Find out how much space we got to play with. $ sudo vgdisplay --- Volume group --- VG Name fedora System ID Format lvm2 Metadata Areas 1 Metadata Sequence No 3 VG Access read/write VG Status resizable MAX LV 0 Cur LV 2 Open LV 2 Max PV 0 Cur PV 1 Act PV 1 VG Size <49.00 GiB PE Size 4.00 MiB Total PE 12543 Alloc PE / Size 4860 / 18.98 GiB Free PE / Size 7683 / 30.01 GiB VG UUID cCXkBg-Z8Or-jmmi-avaK-91VW-v3cF-CmhiKD 2. Resize your logical volume of choice to soak up the space $ sudo lvresize --size +30.01G /dev/fedora/root Rounding size to boundary between physical extents: 30.01 GiB. Size of logical volume fedora/root changed from 15.00 GiB (3840 extents) to 45.01 GiB (11523 extents). Logical volume fedora/root successfully resized. 3. Grow your partition XFS Example: ...

These are my installation notes for creating a lightweight linux desktop environment from scratch, which contains only the most necessary applications. I’ll probably update it slightly in the future, when I realize I have missed some application. It will contain both openbox and dwm, as I’m always torn between using a tiling versus a floating window manager. Mostly I prefer tiling ones, but with some applications, they simply don’t work well. ...

for i in {0..255} ; do printf "\x1b[48;5;%sm%3d\e[0m " "$i" "$i" if (( i == 15 )) || (( i > 15 )) && (( (i-15) % 6 == 0 )); then printf "\n"; fi done

Open local port 5901 to be reached from anyone by connecting to localhost:8080 socat TCP4-LISTEN:8080,fork TCP4:localhost:5901

Description: Install unattended-upgrades. The server should run unattended upgrades every night, and reboot at 4 am if required by any application. Implementation: Login as root Install packages unattended-upgrades and cron-apt Set the following values in /etc/apt/apt.conf.d/50unattended-upgrades Unattended-Upgrade::Origins-Pattern { "o=Debian,a=stable"; }; Unattended-Upgrade::MinimalSteps "true"; Unattended-Upgrade::InstallOnShutdown "true"; Unattended-Upgrade::Mail "root"; Unattended-Upgrade::MailOnlyOnError "true"; Unattended-Upgrade::Remove-Unused-Dependencies "false"; Unattended-Upgrade::Automatic-Reboot "true"; Unattended-Upgrade::Automatic-Reboot-Time "04:00"; Unattended-Upgrade::InstallOnShutdown "false"; Set the following values in /etc/apt/apt.conf.d/02periodic APT::Periodic::Update-Package-Lists "1"; APT::Periodic::Unattended-Upgrade "1"; APT::Periodic::AutocleanInterval "30"; Verification: Run unattended-upgrade --dry-run --debug as root. If there are any application upgrades available, they should show up. Wait a few days and check /var/log/apt/history.log

Clean #! /usr/bin/env expect set host [lindex $argv 0]; set user [lindex $argv 1]; set passwd [lindex $argv 2]; set timeout 5 spawn ssh $user@$host expect { "yes/no" { send "yes\r" exp_continue } "password:" { send "$passwd\r" exp_continue } "$user@$host:~? " { exit 0 } timeout { exit 2 } } exit 1 Wrapped inside bash #! /usr/bin/env bash assert_ssh_login() { local host="${1}" local user="${2}" local passwd="${3}" local details="$(echo -e "\ set timeout 5 \n\ spawn ssh ${user}@${host} \n\ expect { \n\ \"yes/no\" { \n\ send \"yes\r\" \n\ exp_continue \n\ } \n\ \n\ \"password:\" { \n\ send \"${passwd}\r\" \n\ exp_continue \n\ } \n\ \n\ \"${user}@${host}:~? \" {\n\ exit 0 \n\ } \n\ \n\ timeout { \n\ exit 2 \n\ } \n\ } \n\ \n\ exit 1 \n\ " | expect)" case "${?}" in "0") echo "Can login as ${user} on ${host}" ;; "1") echo "${user} can not login on ${host}. Details: ${details}" ;; "2") echo "${user} can not login on ${host} (Timeout). Details: ${details}" ;; * ) echo "${user} can not login on ${host} (Error ${?}): Details: ${details}" ;; esac }

Description: The first step is to establish basic network connectivity for your router/gateway. This will allow you to connect to the installation server on the distribution network, from which you can install the routing software needed in later steps. Your router needs three network interfaces: the loopback interface (lo; which is used for network connections within the gateway) the interface connected to the distribution network (eth1) the interface connected to your network (eth0). Each interface needs an address, netmask and broadcast address. It is important that you specify the correct netmask and broadcast address! ...

Get wpa-psk by running wpa_passphrase MyNetwork MyPassphrase. /etc/network/interfaces should be chmod 0600 if you put the wpa-psk there source /etc/network/interfaces.d/* # The loopback network interface auto lo wlan0 iface lo inet loopback iface wlan0 inet dhcp wpa-ssid MyNetwork wpa-psk a2d024861ef90117c47083c9252d1e9c107c7cc6ab938cd08349c9192d444d2f

Add read/write for group plugdev echo 'KERNEL=="hidraw*", SUBSYSTEM=="hidraw", MODE="0664", GROUP="plugdev"' | sudo tee /etc/udev/rules.d/99-hidraw-permissions.rules # Check that you have the group plugdev groups # If you cannot see plugdev there, type this: sudo usermod -aG plugdev $USER # Now it should work (otherwise reboot or replug usbhid device)

Links Official Guide Before you start Make sure you’ve configured /etc/makepkg.conf Download the package’s PKGBUILD-file from AUR (under View PKGBUILD under Package Actions on the right side) Making Put the PKGBUILD-file in a separate folder, maybe $HOME/tmp cd to the folder run makepkg -s a. Does it want you to install any application? Press yes b. Does it need some other package from AUR? Install that first You should now have a pkg.tar.xz-file. Run pacman -U that.file.name.pkg.tar.xz