git track

07_Linux_Logs_Disk_Management.md

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+# Linux – Logs & Disk Management (Day 7)
+
+## Why Logs Are Important in DevOps?
+Logs tell you:
+- what happened
+- when it happened
+- why something failed
+
+In production, logs are the FIRST place to check.
+
+---
+
+## Log Directory
+Most Linux logs are stored here:
+```bash
+/var/log
+```
+
+List log files:
+```bash
+ls /var/log
+```
+
+Common logs:
+- syslog
+- auth.log
+- kern.log
+- boot.log
+
+---
+
+## View Log Files
+
+### cat (small files)
+```bash
+cat /var/log/syslog
+```
+
+### less (recommended)
+```bash
+less /var/log/syslog
+```
+
+Navigation:
+- Up / Down arrows
+- q → quit
+
+---
+
+## Live Log Monitoring
+```bash
+tail -f /var/log/syslog
+```
+
+Very useful when debugging live issues.
+
+---
+
+## Search Inside Logs
+```bash
+grep error /var/log/syslog
+```
+
+Case-insensitive:
+```bash
+grep -i error /var/log/syslog
+```
+
+---
+
+## Disk Space Management
+
+### Check Disk Usage
+```bash
+df -h
+```
+
+---
+
+### Check Folder Size
+```bash
+du -sh /var/log
+```
+
+---
+
+### Find Large Files
+```bash
+du -ah / | sort -rh | head -10
+```
+
+⚠️ Use carefully (may need sudo)
+
+---
+
+## Clear Log Files (Safe Method)
+```bash
+sudo truncate -s 0 /var/log/syslog
+```
+
+❌ Do NOT delete system log files blindly.
+
+---
+
+## Real DevOps Scenario
+Problem: Server disk full
+
+Steps:
+1. Check disk usage
+2. Identify large directories
+3. Clear old logs safely
+
+Commands:
+```bash
+df -h
+du -sh
+tail -f
+```
+
+---
+
+## Common Mistakes
+- Deleting log files directly
+- Ignoring disk alerts
+- Not monitoring log growth
+
+---
+
+## DevOps Rule
+✅ Monitor logs regularly  
+❌ Ignore disk usage
+
+---
+
+## Summary
+Today I learned Linux log monitoring and disk management.
+These skills are critical for production troubleshooting.

08_Git_Basics.md

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+# Git – Basics for DevOps (Day 8)
+
+## What is Git?
+Git is a version control system.
+It helps you track changes in code and collaborate safely.
+
+DevOps engineers use Git DAILY.
+
+---
+
+## Why Git is Important for DevOps?
+- Track code changes
+- Collaborate with teams
+- Rollback broken deployments
+- CI/CD depends on Git
+
+---
+
+## Install Git
+```bash
+git --version
+```
+
+If not installed:
+```bash
+sudo apt install git
+```
+
+---
+
+## Configure Git (One-time Setup)
+```bash
+git config --global user.name "Your Name"
+git config --global user.email "your@email.com"
+```
+
+Check config:
+```bash
+git config --list
+```
+
+---
+
+## Create a Git Repository
+```bash
+mkdir devops-project
+cd devops-project
+git init
+```
+
+---
+
+## Git Workflow (Basic)
+1. Modify files
+2. Stage changes
+3. Commit changes
+
+---
+
+## Check Repository Status
+```bash
+git status
+```
+
+---
+
+## Add Files to Staging
+```bash
+git add file.txt
+```
+
+Add all files:
+```bash
+git add .
+```
+
+---
+
+## Commit Changes
+```bash
+git commit -m "Initial commit"
+```
+
+---
+
+## View Commit History
+```bash
+git log
+```
+
+Short view:
+```bash
+git log --oneline
+```
+
+---
+
+## Check File Differences
+```bash
+git diff
+```
+
+---
+
+## Undo Changes (Basic)
+
+Undo unstaged changes:
+```bash
+git checkout -- file.txt
+```
+
+---
+
+## Real DevOps Scenario
+Problem: New code broke production
+
+Solution:
+1. Check commit history
+2. Roll back to stable commit
+
+Git saves lives in production.
+
+---
+
+## Common Mistakes
+- Committing without message
+- Forgetting git add
+- Working directly on main branch
+
+---
+
+## DevOps Rule
+✅ Commit small changes  
+❌ Commit everything at once
+
+---
+
+## Summary
+Today I learned Git basics: init, add, commit, status, and log.
+These are core DevOps skills.

09_Git_Branching_Merging.md

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+# Git – Branching & Merging (Day 9)
+
+## Why Branching is Important?
+Branching allows teams to:
+- work on features safely
+- fix bugs without breaking main code
+- collaborate without conflicts
+
+DevOps uses branching DAILY.
+
+---
+
+## What is a Branch?
+A branch is a separate line of development.
+
+Main branch = stable production code  
+Feature branch = new changes
+
+---
+
+## View Branches
+```bash
+git branch
+```
+
+---
+
+## Create a New Branch
+```bash
+git branch feature-login
+```
+
+Switch to branch:
+```bash
+git checkout feature-login
+```
+
+Shortcut (create + switch):
+```bash
+git checkout -b feature-login
+```
+
+---
+
+## Check Current Branch
+```bash
+git branch
+```
+(* shows active branch)
+
+---
+
+## Make Changes in Branch
+```bash
+echo "Login feature" >> login.txt
+git add .
+git commit -m "add login feature"
+```
+
+---
+
+## Merge Branch into Main
+Switch to main:
+```bash
+git checkout main
+```
+
+Merge:
+```bash
+git merge feature-login
+```
+
+---
+
+## Delete Branch (After Merge)
+```bash
+git branch -d feature-login
+```
+
+---
+
+## Merge Conflicts (Important)
+Occurs when same file is changed in two branches.
+
+Git will stop and ask you to fix manually.
+
+Steps:
+1. Open conflicted file
+2. Fix content
+3. Save file
+4. Add & commit
+
+```bash
+git add .
+git commit -m "resolve merge conflict"
+```
+
+---
+
+## Real DevOps Scenario
+Problem: Multiple developers pushing code
+
+Solution:
+- Each dev uses own branch
+- Merge after testing
+
+---
+
+## Common Mistakes
+- Working directly on main
+- Not pulling latest code
+- Deleting branch before merge
+
+---
+
+## DevOps Rule
+✅ One feature = one branch  
+❌ Direct commits to main
+
+---
+
+## Summary
+Today I learned Git branching, merging, and conflict handling.
+This is essential for DevOps collaboration.

10_GitHub_DevOps_Workflow.md

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+# GitHub – DevOps Workflow (Day 10)
+
+## What is GitHub?
+GitHub is a cloud platform to host Git repositories.
+It allows teams to collaborate, review code, and trigger CI/CD pipelines.
+
+DevOps engineers use GitHub daily.
+
+---
+
+## Why GitHub is Important for DevOps?
+- Central code storage
+- Team collaboration
+- CI/CD integration
+- Code reviews and approvals
+
+---
+
+## Create GitHub Account
+Go to https://github.com and create a free account.
+
+---
+
+## Connect Local Repository to GitHub
+
+Create a new repository on GitHub (do NOT add README).
+
+Then run:
+```bash
+git remote add origin https://github.com/username/repo-name.git
+```
+
+Verify:
+```bash
+git remote -v
+```
+
+---
+
+## Push Code to GitHub
+```bash
+git push -u origin main
+```
+
+---
+
+## Clone a Repository
+```bash
+git clone https://github.com/username/repo-name.git
+```
+
+---
+
+## Pull Latest Changes
+```bash
+git pull origin main
+```
+
+---
+
+## GitHub DevOps Workflow
+1. Create feature branch
+2. Push branch to GitHub
+3. Open Pull Request
+4. Code review & approval
+5. Merge to main
+6. CI/CD deploys automatically
+
+---
+
+## Pull Requests (PR)
+A Pull Request is a request to merge code into the main branch.
+Used for safe deployments and team collaboration.
+
+---
+
+## Real DevOps Scenario
+Multiple developers working together:
+- Everyone works on own branch
+- PRs ensure stability
+- CI checks before merge
+
+---
+
+## Common Mistakes
+- Pushing directly to main
+- Not pulling latest changes
+- Ignoring PR reviews
+
+---
+
+## DevOps Rule
+✅ Always use Pull Requests  
+❌ Never push directly to main
+
+---
+
+## Summary
+Today I learned GitHub basics for DevOps including clone, push, pull,
+and Pull Request workflow used in real companies.