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LPI Essentials Notices

• Managing Users and Groups
• Managing File Ownership and Permissions
• Archiving Files
• Managing Linux Processes and Log Files
• Connecting Linux to a Network

8 Managing Users and Groups

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Git - Cheatsheet

Global Settings

Related Setup: https://gist.github.com/hofmannsven/6814278

Related Pro Tips: https://ochronus.com/git-tips-from-the-trenches/

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vimdiff cheat sheet

##git mergetool

In the middle file (future merged file), you can navigate between conflicts with ]c and [c.

Choose which version you want to keep with :diffget //2 or :diffget //3 (the //2 and //3 are unique identifiers for the target/master copy and the merge/branch copy file names).

:diffupdate (to remove leftover spacing issues)

:only (once you’re done reviewing all conflicts, this shows only the middle/merged file)

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Watchdogged

Place the service file (or a link to it) in /etc/systemd/system/ Place the watchdogged.py file somewhere ( and change the ExecStart portion in the .service to point at the file )

then do systemctl daemon-reload followed by systemctl start watchdogged.service

After this you can watch the progress using journalctl --follow -u watchdogged.service change the PROBABILITY variable to something else to watch it faster/later or succeed.

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Ansible - Cheatsheet

ansible-galaxy

Playbook template init with ansible-galaxy

ansible-galaxy init roles/myrole

ansible-playbook

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Add certificate to JRE trusted certificates store

The default JRE store is in:

<JRE>\lib\security\cacerts

Add a certificate with keytool:

<JRE>\bin\keytool.exe -importcert -file my-cert.cer -alias 'My cert' -keystore <JRE>\lib\security\cacerts

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Docker

Images

Remove all images

REPOSITORY          TAG                 IMAGE ID            CREATED             SIZE
hello-world         latest              fce289e99eb9        4 months ago        1.84kB

$ docker rmi $(docker image ls --format "{{.ID}}")

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PGP Guide

GPG vs PGP

PGP can refer to two things:

The Pretty Good Privacy software originally written by Phil Zimmermann, and now owned by Symantec. The formats for keys, encrypted messages and message signatures defined by that software. These have now been formalised as the OpenPGP standard. The GPG software is an independent implementation of the OpenPGP standards, so you can use it to exchange encrypted messages with people using other OpenPGP implementations (e.g. Symantec's PGP).

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A common and reliable pattern in service unit files is thus:

NoNewPrivileges=yes
PrivateTmp=yes
PrivateDevices=yes
DevicePolicy=closed
ProtectSystem=strict
ProtectHome=read-only
ProtectControlGroups=yes
ProtectKernelModules=yes

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Git - Cheatsheet & Tips

Although there are enough resources on the web about Git, I will keep this one for my own reference. Minimal Git version required 1.7.2.

TOC

• Info
• Adding
• Branching
• Patching