once more: verify files with pgp – f-droid.org verify apk download gpg signature asc sig – md5sum and sha512sum linphone app

md5 signatures could be forged, sha512sums imho not yet, but checking those crc checksums is straight forward, all one needs is the checksum md5sum for org.linphone_4125.apk should be 3efee7b3b836a72abf327edc55daa4ba sha512sum for org.linphone_4125.apk should be 3f99cfec851f6105d549c2914b7a823467053d11a67cb6d98244202b850d13413fb1cbc52dfacd5d1260cc77409f242d4b0ed0c94aed0fc38cebc4803fdd144f similar to gpg one downloads […]

building a riscv pc – riscv fedora emulator in javascript in browser

RISC-V hardware would definitely recommend to support this project.: if one has little money: https://www.crowdsupply.com/sifive/hifive1-rev-b ($60) with massive amounts of money… https://www.crowdsupply.com/sifive/hifive-unleashed ($1000) + https://www.crowdsupply.com/microsemi/hifive-unleashed-expansion-board ($2000) one can even build one’s own risc-v pc: (one can only hope that mass production […]

compile rust hello world for arm7

why is RUST so popular? one surely does not want metal to rust… it’s named after a fungi. „Rust is named after a fungus that is robust, distributed, and parallel. It is also a substring of „robust“.“ (src) https://www.quora.com/Why-is-Rust-becoming-popular (he […]

debian centos cups – set default printer and print from bash terminal command line

terminal/bash/no gui version: hostnamectl; # tested on Operating System: CentOS Linux 7 (Core) CPE OS Name: cpe:/o:centos:centos:7 Kernel: Linux 4.15.9 Architecture: x86-64 # with software installed yum list installed|grep cups cups.x86_64 1:1.6.3-35.el7 @base cups-client.x86_64 1:1.6.3-35.el7 @base cups-filesystem.noarch 1:1.6.3-35.el7 @base cups-filters.x86_64 […]


for whatever reason, it is not enough to allow udp traffic on port 5900, one also needs to allow tcp traffic. /sbin/iptables -A INPUT -p tcp -m tcp –dport 5900 -j ACCEPT /sbin/iptables -A INPUT -p udp -m udp –dport […]


yum install ascii # or apt install ascii ascii Usage: ascii [-dxohv] [-t] [char-alias…] -t = one-line output -d = Decimal table -o = octal table -x = hex table -h = This help screen -v = version information Prints […]

Windows (7) automatic reboot every 3 days at midnight taskschd.msc

sometimes one wants to restart a windows vm every x days – to clean up RAM and Co. run task scheduler „Aufgabenplanung“ %windir%\system32\taskschd.msc /s File/Datei -> New/Neu -> Basic Task/Einfache Aufgabe select or copy paste: %SystemRoot%\System32\shutdown.exe one has to scroll […]


when one is happy with the setup of a linux system (config and scripts) one might want to backup those settings and restore it on a different machine or if things go haywire restore on the current machine. cat /scripts/backup/config_scripts.sh […]


# tested on CentOS Linux 7 (Core) dig -v DiG 9.9.4-RedHat-9.9.4-74.el7_6.1 vim /scripts/what_is_my_public_ip.sh echo „my public (internet facing) ip is:“ # echo „asking opendns…“ # kind of failed: (does not return anything) # dig +short myip.opendns.com @resolver1.opendns.com echo „asking google…“ […]