Linux

so Linux-Zeugs, das ich immer wieder vergesse, weil ich es doch nicht jeden Tag brauche, aber immer wieder…

Linux Kleinzeugs
Docker Kleinzeugs
Helm
keeping overview over the Linux System:
legacy
1. quick and dirty manual install of JDK 11 on Ubuntu 18.04

Linux Kleinzeugs

reset the screens (Trick Robert):

ctrl-alt-F7 ... ctrl-alt-F1

history completition

ctrl-r

tab-switcher behaviour

gsettings set org.gnome.shell.app-switcher current-workspace-only true

rpm on ubuntu:

alien -i bla.rpm

distribution:

cat /etc/*release*
lsb_release -a

Ubuntu full update:

update-manager -c -d

Kleinzeugs Netzwerk:

nmap -p 5000 172.30.1.1
[luna:~] rschumm% sudo nmap -PR 192.168.1.0/24 -sn

Kleinzeugs

watch -n 1 befehl

ugo Zeugs:

r=4
w=2
x=1

quickshell:

bash -c 'for i in {1..110}; do mkdir "$i"; done'

sudo vi /usr/share/gnome-shell/theme/ubuntu.css
Sektion lockDialogGroup 

zip, tar

zip -r zipFileNameOhneZip Ordner (packen)
unzip zipFileName.zip (entpacken)

tar -cvz Ordner -f tgzFileName.tgz (packen)
tar -xvzf tgzFileName.tgz (entpacken)

size rekursiv

du -sh -d 1 .

git stuff

see here

scp stuff

quick scp

scp luna:file .     (copy file in home of luna to here)
scp file remy@kassandra: (copy file from here to home of kassandra)

ssh stuff

use a special key for git clone

in .ssh/config

host companygit
    Hostname code.company.com
    IdentityFile ~/.ssh/long_19_id_rsa
    IdentitiesOnly yes

and then replace the hostame in the git url:

git clone git@companygit:team/myRepo.git

add key:

echo 'ssh-rsa AAA... bla bla = rschumm@luna' >> authorized_keys

keygen and list type:

ssh-keygen 
ssh-keygen -t rsa 
ssh-keygen -lv -f id_rsa

change key password:

ssh-keygen -p

on macOS (agent)

add to keychain, if you use a password: 
ssh-add ~/.ssh/id_rsa
ssh-add --apple-use-keychain ~/.ssh/id_rsa
ssh-add l

für .ssh, ugo-Zeugs:

chmod 700 ~/.ssh
chmod 644 ~/.ssh/authorized_keys
chmod 600 id_rsa 

für git und ssh siehe hier.

ssh Tunnel:

hier als Alias in zsh:

alias tunnelprod='ssh -fNT -L (localport):db.prod.ch:(originalport) -L (noch mehr) remy.schumm@db.prod.ch' 

note: this will expose the IP of db.prod.ch to the target system. To expose localhost (of the target system) use:

alias tunnelprod='ssh -fNT -L (localport):localhost:(originalport) -L (noch mehr) remy.schumm@db.prod.ch' 

the tunnel will still go to the target host mentionned in the last argument of the command.

SSL / Cert stuff

check private key:

openssl rsa -in pkey.pem -check

expected: RSA key ok

check certificate:

openssl x509 -in cert.pem -text

expected: all the info

users und so

sudo useradd --create-home --groups sudo cloud-user
sudo passwd cloud-user

Bem: useradd nur für simple user, adduser sollte alles machen, inkl. home-dir. cf Cheat

sudo usermod -aG sudo cloud-user
userdel -r cloud-user

regex, sed etc.

echo 'hallo welt' | sed 's/welt/winterthur/'

firewall

RHEL etc.

firewall-cmd --list-all
firewall-cmd --zone=public --add-port=8080/tcp
firewall-cmd --zone=public --remove-port=8080/tcp
firewall-cmd --zone=public --list-ports

garbage

logs and caches:

sudo journalctl --vacuum-time=10d
sudo apt-get clean

alternatives

update-alternatives --list java
sudo update-alternatives --config java
update-alternatives --install ... 

update-alternatives --query mvn
to install:  --install <Link> <Name> <Pfad> <Priorität>
sudo update-alternatives --install /usr/bin/mvn mvn /home/rschumm/Software/apache-maven-3.6.0-bin/apache-maven-3.6.0/bin/mvn 100

to set JAVA_HOME: find out where Java is with: update-alternatives --config java, then, in .bashrc:

export JAVA_HOME="/usr/lib/jvm/jdk-11.0.2+9"

tcsh

set path = ($path $HOME/.gem/ruby/2.3.0/bin/ .)
set path = (/Applications/maven/apache-maven-3.6.3/bin $path:q)
setenv  M2_HOME /Applications/maven/apache-maven-3.x.x
alias mvn $M2_HOME/bin/mvn

alias 2x mit Parameter, einmal normal und einmal frei: 
alias studrepos java -jar /Users/rschumm/zhaw/1974/git/praktikumgit/target/praktikumgit.jar
alias heute 'curl -i  -H "Content-Type: application/yaml" -X POST http://localhost:8080/stunden/heute --data-binary @\!:1'
alias lösche 'curl -i -X DELETE http://localhost:8080/stunden/tag/\!:1'

alias reload source ~/.tcshrc

bash und zsh

export PATH="/home/rschumm/minis/minishift-1.18.0-linux-amd64/:$PATH"
echo $PATH
printenv

alias and such:

alias schummsync='rsync -vrtz _site/* xxx@xxx.xxx.hostpoint.ch:~/www/public_html/schumm/'

#function will be accessible just like an alias: 
open() {
    #open the explorer just like in macOS
    nautilus "$1" & 
}

Bemerkung: Sachen wie @\!:1 funktionieren in zsh nicht! Da muss eine Funktion her.

Beipiel: ruft ein Java-Programm auf und lässt das OpenShift Command laufen:

#!/bin/bash

java Generator.java
#(needs JDK 11)

for file in $(find . -iname '*.yml'); do 
     echo "$file"
     #ls -l "$file"
     oc create -f "$file"
done

Partition resize in RHEL

Partition sda2 füllt nicht die ganze Disk, ich will sie auf das Maximumm vergrössern:

sudo su - 
fdisk /dev/sda

p

d

n

p

..dann auch alles default... 

w

reboot

xfs_growfs /dev/sda2

Docker Kleinzeugs

general

docker pull
docker login -u user -p token 

docker images
docker image ls
docker image rm 

garbage collect docker:

docker images 
sudo docker system prune -a

quick interactive container with docker run:
Docker Run CLI Reference

docker run -it --rm ubuntu /bin/bash

run a simple container (with a webapp inside) (localport:containerport)

rschumm@kassandra:~$ docker run -i --rm -p 8080:8080 schumm/mywebapp

run a new container (with interacting local data)

docker run -it --rm --entrypoint /bin/bash quay.io/quarkus/centos-quarkus-maven:graalvm-1.0.0-rc14

…with a local directory mounted as a volume, here e.g. /project (note: the local dir must be chmod o+w). This examples runs a source to build image and then starts the mvn build in this container.

docker run -it  --entrypoint /bin/bash --rm -v /home/rschumm/git/halloquarkus:/project quay.io/quarkus/centos-quarkus-maven:19.0.2
mvn clean verify -Pnative -DskipTests 

attach to an already running container

docker ps 
docker exec -it 91e /bin/bash

save a docker image as file:

rschumm@kassandra:~$ docker save -o schumm.tar schumm/myimage

Helm

tl;dr:

helm repo list
helm repo add dings https://charts.dings.io
helm repo update

helm search repo dings --versions
helm show chart dings/dings-chart  
helm show all dings/dings-chart  

on cluster: 
helm install dings dings/dings -n k8sns
helm upgrade dings dings/dings -n k8sns

keeping overview over the Linux System:

install Cockpit

Cockpit

legacy

quick and dirty manual install of JDK 11 on Ubuntu 18.04

n.b.: finally, in ubuntus jdk11 is also jdk11 inside like it’s «written on the box». So no need anymore for this.

update-java-alternatives -l | -s

download the jdk11 and untar it in /usr/lib/jvm, in my sample: jdk-11.0.2+9
run the update-alternatives for every binary, which is done by following snippets:

% sudo sh -c 'for bin in /usr/lib/jvm/jdk-11.0.2+9/bin/*; do update-alternatives --install /usr/bin/$(basename $bin) $(basename $bin) $bin 100; done'

% sudo sh -c 'for bin in /usr/lib/jvm/jdk-11.0.2+9/bin/*; do update-alternatives --set $(basename $bin) $bin; done'

then choose the installation with update-alternatives --config java

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