> For the complete documentation index, see [llms.txt](https://arekczarny.gitbook.io/grimoire/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://arekczarny.gitbook.io/grimoire/spells.md).

# Userful Spells

## Linux

### Impersonate

* sudo su --> becoming root when user in sudoers
* sudo su - root --> becoming root
* sudo -su user --> becoming user
* sudo su -s /bin/sh jenkins --> becoming jenkins (service account)

### Linux kernel checks

* cat /etc/os-release
* lsb\_release -a
* uname -r --> Linux kernel version

### File system & disk operations

* ls -t -> list files sorts last modified newest on top
* ls -tr -> same as above reversed
* find . -type f -exec dos2unix {} ; --> convert line endings in the whole directory tree
* sudo ln -s /opt/maven/bin/mvn /usr/bin/mvn
* sudo ln -s /usr/share/groovy/groovy-2.5.7/bin/groovy /usr/bin/groovy
* du -sh /etc/ --> report only the total disk space occupied by a directory tree and to suppress subdirectories
* du -sh ./\*/ --> list out total memory for each subfolder in current path
* du -a -h /etc/ --> same as above + including files not only dirs
* du -ch \*.png --> see the size of each png file in the current directory
* du -a /etc/ | sort -n -r | head -n 10 --> List top 10 directories eating disk space in /etc/
* df -h --> report file system disk space usage in human form
* df -h --total --> option to have the total

### SSH connection & file operations

* ssh-add -c mykeypair.pem --> Linux add private key to the authentication agent
* ssh-add -K mykeypair.pem --> MacOS same as above
* ssh -A @ --> ssh to host machine, then connect to any host that has same private key for authentication
* ssh -i \~/.ssh/id\_rsa.pub USER\@SERVER
* scp -i \~/.ssh/id\_rsa.pub FILENAME USER\@SERVER:/home/USER/FILENAME

### Administration commands

* sudo -l --> lists all privileges from /etc/sudoers for a user
* sudo -s --> inherits your current user environment
* sudo -i --> gives clean environment, like you get just after login
* sudo update-alternatives --config editor -> changes visudo editor
* sudo visudo -> launches the /etc/sudoers file in an editor
* sudo visudo -f /etc/sudoers.d/file\_to\_edit -> launches any other sudoers file in visudo
* [SUID](http://www.linuxnix.com/suid-set-suid-linuxunix/)

### Linux LIMITS checking and changing of them

* cat /proc/sys/kernel/pid\_max --> shows maximum number of processes particular kernel can run
* cat /proc/PID/limits --> shows limits of a particular process
* ulimit -a --> shows limits for a user that executes it
* ulimit -Hu --> shows hard limits for max user processes (-u)
* ulimit -Su --> shows soft limits for max user processes (-u) you can add any letter from -a list for this to check the limit
* /etc/security/limits.conf --> This file enforces limits on users/groups etc.
* /etc/security/limit.d/ --> Files in this directory overrides any settings done in limits.conf file. Files here are being read in the alphabetical order and that is how settings are also being overridden.

### Linux services

* service --status-all --> lists all services on linux
* chkconfig --add myscript --> adds a service to run level
* chkconfig --level 2345 myscript on --> enable it for particular run level
* chkconfig --level 2345 myscript off --> removes from run level
* chkconfig --del myscript --> removes service from chkconfig
* chkconfig --list | grep myscript --> linsts chkconfig service

### Linux servivces systemD

* systemctl list-units --type=service --> list all services
* systemctl start \<service\_name>
* systemctl stop \<service\_name>
* systemctl status \<service\_name>
* systemctl enable \<service\_name> --> enables service\_name to start at OS boot
* systemctl daemon-reload --> reloads SystemD after e.g. adding service file manually
* /etc/systemd/system/\<service\_name>.service --> path for systemd unit files
* /usr/lib/systemd/system/\<servivce\_name>.service --> Amazon Linux 2 systemd unit files from Amazon Repository

### User / Group commands

* cut -d: -f1 /etc/passwd --> lists all users
* useradd -c "Linux user" -d /home/linuxuser -u 1000 -g 1000 -m linuxuser --> creates linuxuser user with /opt/linuxuser as home
* userdel USERANME --> removes user from the sytem
* usermod -aG wheel linuxuser --> add user linuxuser to wheel group
* gpasswd -a user group --> adds user to a group
* gpasswd -d user group --> removes user froma group
* groupadd linuxuser --> adds linuxuser group
* groupadd -g 1000 linuxuser --> adds linuxuser group with groupid 1000
* sudo chgrp -R tomcat /opt/tomcat --> Give the tomcat group ownership over the entire installation directory:
* sudo chmod -R g+r conf --> give the tomcat group read access to the conf directory and all of its contents
* sudo chmod g+x conf --> give the tomcat group execute access to the conf directory
* sudo chown -R tomcat webapps/ work/ temp/ logs/ --> make the tomcat user the owner of the webapps, work, temp, and logs directories:
* groups --> lists all current user's groups
* cut -d: -f1 /etc/group --> Lists all the groups in the system
* groupdel GROUPNAME --> deletes group from system

### Finding all files containing a text string on Linux

* grep -rnw 'directory' -e "pattern" -> -r or -R is recursive, -n is line number and -w stands match the whole word. -l (letter L) can be added to have just the file name.
* grep --include=\*.{c,h} -rnw 'directory' -e "pattern" -> Along with these, --exclude or --include parameter could be used for efficient searching.
* grep --exclude=\*.o -rnw 'directory' -e "pattern" -> Above will exclude searching all the files ending with .o extension.
* grep --exclude-dir={dir1,dir2,\*.dst} -rnw 'directory' -e "pattern" -> Just like exclude file it's possible to exclude/include directories through --exclude-dir and --include-dir parameter, the following shows how to integrate --exclude-dir
* grep -rl . -e "pattern" -> gives only the file names where pattern is located.

### Find all unique extensions of files in root and subfolders exclude .git directory

* find . -type f -path '\*/.git\*' -prune -o -print | sed -rn 's|.\*/\[^/]+.(\[^/.]+)$|\1|p' | sort -u
* Same as above with multiple directories
* find . -type d (-path '\*/.git\*' -o -path '\*/.idea\*' ) -prune -o -print | sed -rn 's|.\*/\[^/]+.(\[^/.]+)$|\1|p' | sort -u

### Untar \ Unzip compressed stuff

* zip -r plugins.zip plugins/ --> zips plugins directory (in current location) into plugins.zip file
* zip -r -s MaximumSize ArchiveName.zip FolderName/
* tar xvzf maven.tar.gz -C /var/jenkins\_home/apache-maven/ -> untar to specified location
* unzip /usr/share/zip\_file.zip -d /home/linuxuser/tmp/build/

### Checking TLS connections to server

* openssl s\_client -connect domain.dupa.net:636 -tls1\_2 --> checks server for TLS1.2 connection
* openssl s\_client -connect domain.dupa.net:636 -showcerts
* nmap --script ssl-enum-ciphers -p 636 domain.dupa.net --> Lists all possible TLS connections and ciphers

## Docker

* docker build -t username/repository .
* docker build -t username/repository:latest -t username/repository:1.00-0 . --> builds image and tags with latest and specific version

### Run containers

* docker ps -> running containers
* docker ps -a -> all containers
* docker exec -it --user root username/repository:latest /bin/bash
* docker exec -it username/repository:latest /bin/sh
* docker run -it --rm -p 8080:8080 --name \<container\_name> username/repository:latest /bin/bash

### Containers Images management

* docker pull microsoft/mssql-server-linux -> updates image
* docker rm container\_name -> removes docker container
* docker rmi image\_name -> removes docker image from local repository

### Docker Volumes / Files

* docker volume ls -> lists volumes
* docker cp file.txt \<container\_name>:/directory/file.txt -> copies files from host to container
* docker cp \<container\_name>:/directory/file.txt x:\directory\file.txt-> copies files from container to host

### Docker network

* route | awk '/^default/ { print $2 }' --> execute from within running container to get HOST IP address

### Inspect / monitor / troubleshoot containers

* docker inspect container\_name -> shows container data
* docker events -> show what is happening in the container and
* docker logs -> shows logs from failed container

### Docker for Windows:

1. Check that you have the proper credentials setup under Credentials Manager->Windows Credentials->Dockerhost Filesystem Access <https://forums.docker.com/t/volume-mounts-in-windows-does-not-work/10693/45>

## Git

### Repository Operations

* git remote -v --> view existing remotes
* git remote rename origin old\_origin --> Change remote name from 'origin' to 'old\_origin'
* git remote set-url origin git\@server:group/project/project.git
* git remote set-url origin [https://server:group/project/project.git](https://arekczarny.gitbook.io/grimoire/https:/server:group/project/project.git)
* git remote add origin git\@server:group/project/project.git
* git pull origin master
* git branch --set-upstream-to=origin/master master && git pull
* git remote remove origin

### Basic operations

* git checkout \<branch\_name> --> checks out branch
* git push --> pushes current branch into remote repository
* git branch -D \<feature\_branch> --> deletes local \<feature\_branch>
* git push origin :feature\_branch --> pushes "an empty branch" into origin/feature\_branch thus deleting remote branch

### Merge/Rebase

* git merge-base \<feature\_branch> --> find \<commit\_id> of original base () for current \<feature\_branch>
* git rebase -i \<commit\_id> --> this will start rebasing from the base on which feature\_branch was created
* git rebase -i HEAD\~3 --> if you just want to clean up few latest commits this is useful. Will do rebase from the point where 3rd last commit occurred
* git rebase -i master --> rebasing current branch onto master branch
* git merge --no-ff \<feature\_branch> --> merges \<feature\_branch> into current branch with no fast-forward (with merge commit)

### Tagging

* git tag -> list tags
* git show v1.4 -> shows tag data with the commit
* git tag -a v1.4 -m "my version 1.4" -> creates annotated tag !
* git tag -a v1.2 9fceb02 -> tag specific commit later
* git tag -a 4.4.9.Release\_Final -m "Final 4.4.9.Release tag" 706b8e9 -> tag specific commit with comment later
* git tag v1.4-lw -> creates lightweight tag
* git push origin 4.4.5.Release\_Final -> push explicite tag
* git push origin --tags -> all tags pushed
* git checkout -b version2 v2.0.0 -> checkout tag v2.0.0 into version2 branch
* git push origin :tagname - removes tagname from origin
* git push --delete origin tagname - same as above with delete more explicit
* git tag --delete tagname - delete local tagname

### Blogs, adivces

* [How to mirror a git repo to a new remote](https://makandracards.com/makandra/48818-how-to-mirror-a-git-repo-to-a-new-remote)
* [Gitkurwa - Jakub Nabrdalik](https://github.com/jakubnabrdalik/gitkurwa)

## Maven

* mvn help:effective-pom --> shows what pom has and what was inherited from parent pom

### Dependencies related stuff

* mvn -o dependency:list -DincludeScope=compile -DoutputFile=dependencies.txt -DexcludeTransitive=true --> list of dependencies
* mvn -o dependency:tree -DoutputType=text -DoutputFile=text.txt -Dverbose --> List of dependeny trees
* mvn install:install-file -Dfile="X:\some\_file-1.0.0.jar" -DgroupId="com.example" -DartifactId=some-artifact -Dversion="1.0.0" -Dpackaging=jar --> Install 3rd Party dependency to local maven repo

### Maven Surefire Plugin (test)

* mvn -Dtest=TestCircle test --> run a single test class
* mvn -Dtest=TestCi\*le test --> patterns to run a number of tests
* mvn -Dtest=TestSquare,TestCi\*le test --> multiple names/patterns, separated by commas
* mvn -Dtest=TestCircle#mytest test --> as of Surefire 2.7.3, you can also run only a subset of the tests in a test class
* mvn -Dtest=TestCircle#test\* test --> patterns can also be used
* mvn -Dtest=TestCircle#testOne+testTwo test --> Since of Surefire Plugin 2.19 you can select multiple methods (JUnit 4, JUnit 4.7+ and TestNG)

### Maven Release Plugin

* mvn -P arekTest release:clean --> clean the release stuff
* mvn -P arekTest release:rollback --> rollbacks all the changes
* mvn clean release:prepare release:perform -P arekTest -DdevelopmentVersion=1.0.0-SNAPSHOT -DreleaseVersion=1.0.0.Release -DskipTests=true -DdryRun=false -DignoreSnapshots=true -DscmCommentPrefix="Some Comment"

### Maven Deploy using deploy-plugin

* mvn clean install
* mvn -P release deploy -DskipTests -Dmaven.install.skip=true

### Maven update poms versions

* mvn -P release versions:set -DnewVersion=1.1.0-SNAPSHOT -DgenerateBackupPoms=false
* mvn versions:revert
* mvn --batch-mode -P release release:update-versions -DdevelopmentVersion=1.1.0-SNAPSHOT

## RabbitMQ

Create a new credentials using command line and use it to connect to RabbitMQ.

* $ rabbitmqctl add\_user
* $ rabbitmqctl set\_user\_tags administrator
* $ rabbitmqctl set\_permissions -p / ".*" ".*" ".\*"

## MacOS

### Shortcuts

* cmd+shift+3 --> saves whole screen to file on Desktop
* cmd+shift+4 --> saves selected stuff to file on Desktop
* cmd+shift+5 --> opens setting window with recording option
* ctrl+cmd+shift+4 --> copies selected stuff to Clipboard

## AWS (CLI, SDK)

### EC2

* aws ec2 start-instances --instance-ids i-0ac8092a3dc1e87d1 --region us-east-1 --> starts an instance
* aws ec2 stop-instances --instance-ids i-0bd1da4bba7cd8a94 --region us-east-1 --> stops an instance
* aws ec2 describe-instances --region us-east-1 --filters "Name=instance-id,Values=i-5ee54ba6"
* aws ec2 describe-instances --region us-east-1 --filters "Name=tag:DummyTag,Values=Shared" --> filters out instances with tag value
* aws ec2 describe-instances --region us-east-1 --filters "Name=instance-state-code,Values=16" > running.txt --> running instances
* aws ec2 describe-instances --filters 'Name=tag:Name,Values=dev-server-*' --output text --query 'Reservations\[*].Instances\[\*].InstanceId'

### Security groups

* aws ec2 describe-security-groups --group-names LDAP

### LOAD BALANCER

* aws elbv2 describe-load-balancers --> describes all LBs on your account
* aws elbv2 describe-load-balancers --load-balancer-arns arn:aws:elasticloadbalanci --> describe ALB
* aws elbv2 describe-listeners --listener-arns arn:aws:tlalal --> describe ALB listeners
* aws elbv2 describe-listeners --listener-arns arn:aws:elasticloadbalancing:us-east-1:366703173583:listener/app/LinuxClustered656-LB/ded2e0f3e2c9e3e8/c0aa6620121a7c6d --> describe ALB listeners
* aws elbv2 describe-listeners --load-balancer-arn arn:aws:elasticloadb --region us-east-1 --output json --query 'Listeners'
* aws elbv2 describe-listeners --load-balancer-arn arn:aws:elasticloadbalancing:us-east-1 --region us-east-1 --output json --query 'Listeners\[0].ListenerArn'
* aws elbv2 describe-target-groups --load-balancer-arn arn:aws:elasticloadbalancing:us-east-1:
* aws elbv2 describe-target-health --target-group-arn arn:aws:elasticloadbalancing:us-east-1:

### STACKS

* aws cloudformation list-stacks --stack-status-filter CREATE\_COMPLETE --region us-east-1 --> list stacks
* aws cloudformation list-stack-instances --stack-set-name lifesaver

### S3 bucket

* aws s3 cp \<file\_name> s3://\<bucket\_name>/\<folder\_name>/\<file\_name>
* aws s3api list-buckets --query "Buckets\[].Name" --> list buckets on S3
* aws s3 ls s3://pbeo-files --recursive --> list files in the folder with recursion