added day 9 task

Author: LondheShubham153

2026/day-09/README.md

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+# Day 09 – Linux User & Group Management Challenge
+
+## Task
+Today's goal is to **practice user and group management** by completing hands-on challenges.
+
+Figure out how to:
+- Create users and set passwords
+- Create groups and assign users
+- Set up shared directories with group permissions
+
+Use what you learned from Days 1-7 to find the right commands!
+
+---
+
+## Expected Output
+- A markdown file: `day-09-user-management.md`
+- Screenshots of command outputs
+- List of commands used
+
+---
+
+## Challenge Tasks
+
+### Task 1: Create Users (20 minutes)
+
+Create three users with home directories and passwords:
+- `tokyo`
+- `berlin`
+- `professor`
+
+**Verify:** Check `/etc/passwd` and `/home/` directory
+
+---
+
+### Task 2: Create Groups (10 minutes)
+
+Create two groups:
+- `developers`
+- `admins`
+
+**Verify:** Check `/etc/group`
+
+---
+
+### Task 3: Assign to Groups (15 minutes)
+
+Assign users:
+- `tokyo` → `developers`
+- `berlin` → `developers` + `admins` (both groups)
+- `professor` → `admins`
+
+**Verify:** Use appropriate command to check group membership
+
+---
+
+### Task 4: Shared Directory (20 minutes)
+
+1. Create directory: `/opt/dev-project`
+2. Set group owner to `developers`
+3. Set permissions to `775` (rwxrwxr-x)
+4. Test by creating files as `tokyo` and `berlin`
+
+**Verify:** Check permissions and test file creation
+
+---
+
+### Task 5: Team Workspace (20 minutes)
+
+1. Create user `nairobi` with home directory
+2. Create group `project-team`
+3. Add `nairobi` and `tokyo` to `project-team`
+4. Create `/opt/team-workspace` directory
+5. Set group to `project-team`, permissions to `775`
+6. Test by creating file as `nairobi`
+
+---
+
+## Hints
+
+**Stuck? Try these commands:**
+- User: `useradd`, `passwd`, `usermod`
+- Group: `groupadd`, `groups`
+- Permissions: `chgrp`, `chmod`
+- Test: `sudo -u username command`
+
+**Tip:** Use `-m` flag with useradd for home directory, `-aG` for adding to groups
+
+---
+
+## Documentation
+
+Create `day-09-user-management.md`:
+
+```markdown
+# Day 09 Challenge
+
+## Users & Groups Created
+- Users: tokyo, berlin, professor, nairobi
+- Groups: developers, admins, project-team
+
+## Group Assignments
+[List who is in which groups]
+
+## Directories Created
+[List directories with permissions]
+
+## Commands Used
+[Your commands here]
+
+## What I Learned
+[3 key points]
+```
+
+---
+
+
+## Troubleshooting
+
+**Permission denied?** Use `sudo`
+
+**User can't access directory?**
+- Check group: `groups username`
+- Check permissions: `ls -ld /path`
+
+---
+
+## Submission
+1. Fork this `90DaysOfDevOps` repository
+2. Navigate to `2026/day-09/` folder
+3. Add your `day-09-user-management.md` with screenshots
+4. Commit and push
+
+---
+
+## Learn in Public
+Share your Day 09 progress on LinkedIn:
+
+- Post about completing the user management challenge
+- Share one thing you figured out
+- Mention real-world DevOps use
+
+Use hashtags:
+```
+#90DaysOfDevOps
+#DevOpsKaJosh
+#TrainWithShubham
+```
+
+Happy Learning
+**TrainWithShubham**