Linux.md

DevSecOps-Pro

Notes for future / Exam

show a text document on a terminal.

cat

Log into a remote machine using ssh protocol.

ssh

Change the file permissions(read, write and execute).

chmod
``
# Download, Upload and copy a git repository.
'''bash 
git (git pull, git push, git add, git clone) 

Change directory, cd django.nv takes you into a django.nv folder.

cd

Become another user (here deploy_user).

sudo su - deploy_user 

Output/echo a string/number on a terminal.

echo 

Exit a program with exit code as 1, usually fails a program when used.

exit 1 

Used to create a directory.

mkdir

An easy to use Text editor.

nano

Save output to file

cat /etc/passwd > mypasswd.txt

Append to exisitng file (add new content to file)

cat /etc/passwd >> mypasswd.txt

Extract content from file

cat mypasswd.txt | cut -d ':' -f 1
Behind the scenes, the cat command’s output was sent to the cut command as an input, and it used -d (delimiter) flag with a colon as a separator/delimiter and -f (field) option to get the 1st field.

-d - delimter flag 
-f - field (to get first field)

Exit Codes

The exit code returned by a program could be obtained through echo $?

Exit Codes with Security Tools

In the context of security tooling, unsuccessful execution generally means that the security tool found vulnerabilities.

In many cases, a mature security tool would return an exit code of zero indicating that the tool found no vulnerabilities.
A mature security tool would return a non zero exit code indicating that the tool found one or more security vulnerabilities.

Git Basics

Configure Username:-
git config --global user.email "[email protected]"
git config --global user.name "student"

Download repository
git clone http://root:pdso-training@gitlab-ce-xcs30z62.lab.practical-devsecops.training/root/django-nv.git

Add file to respsitory
git add myfile README.md

Commit changes to repo
git commit -m "Add myfile and update README.md"

Pull
git pull - pull/download repo to local repo

Push
git push - upload/push local repo to repo

SSH Basics

ssh -o "StrictHostKeyChecking=no" -i ~/.ssh/id_rsa root@prod-xcs30z62

Add keys to known_hosts file

ssh-keyscan -t rsa prod-xcs30z62 >> ~/.ssh/known_hosts

jq

jq '.' learnjq.json

jq '.[] | .details' learnjq.json
jq '.[] | {name: .details.name, url:.details.url}' learnjq.json
jq '.[1] | {name: .details.name, url: .details.url}' learnjq.json
jq '[.[] | {name: .details.name, url: .details.url}]' learnjq.json
jq '.[] | {name: .details.name, url: .details.url, services: .services[]}' learnjq.json
jq '.[] | {name: .details.name, url: .details.url, services: [.services[]]}' learnjq.json
jq '.[] | {name: .details.name, servicecount: .services | length}' learnjq.json
jq '.[] | select(.details.name=="AWS")' learnjq.json
cat bandit-output.json | jq .metrics._totals.'"CONFIDENCE.HIGH"'