Hello from Quang
Run cmd in the background : cmd + &  link : makeuseof.com/run-linux-commands-in-background/ 
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PACKAGE -
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1. download a package 
  sudo apt-get install --reinstall --download-only <name_package>
2. modify a package 
Copy the deb file to a directory

Create the directory structure
$ mkdir -p newpack oldpack/DEBIAN

Extract the filesystem tree
$ dpkg-deb -x file.deb oldpack/

Extract the control information files
$ dpkg-deb -e file.deb oldpack/DEBIAN

Modify something if you want

Repackage the deb file under newpack directory using xz compression
$ dpkg-deb -Z xz -b oldpack/ newpack/ 

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DOCKER -
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GIT  ---
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1. Get started 
git innit 
2. create a github account + add ssh key 
 cd $HOME
 ls -la .ssh
ssh-keygen -t ed25519
:.ssh> cat id_ed25519.pub

3. git add <files>
4. git commit -m + <mesgae>
5. git push orgin + branch_name
6. git pull origin + branch
7. git merge + branch a + branch b 
8. git reset --soft HEAD~<commit_id>
9. git log 
10. git show + <commit_id>
11. git reset --hard HEAD~<number>
12. git rebase a 
13. git rebase master
14. git checkout <name_branch>
15. git branch <name_branch>

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pip3 install -
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--upgrade : 
--no-index : ignore package index (only looking at --find-link) 
--find-link : 
. if a URL or path to an html file, then parse for links to archives such as sdist (.tar.get)
for wheel(.whl) files.
. if a local path or file:// URL that;s a directory, then look for archies in the directory listing. 

-t + path + name 
-t, --target <dir> : install packages into <dir>