Shailesh Gokhale

Posted on Aug 19, 2024

Today I learned basics of linux commands, below commands are sufficient for devOps please guide someone.

#devops #docker #git #linux

Here are some essential Linux commands that are frequently used in DevOps for managing systems, automating tasks, and deploying applications:

1. File and Directory Management

ls: List files and directories.

 ls -la  # List all files with detailed information

cd: Change directory.

 cd /path/to/directory  # Navigate to a specific directory

cp: Copy files or directories.

 cp file1.txt file2.txt  # Copy file1.txt to file2.txt
 cp -r /src /dest  # Copy a directory recursively

mv: Move or rename files and directories.

 mv oldname.txt newname.txt  # Rename a file
 mv /src /dest  # Move a file or directory

rm: Remove files or directories.

 rm file.txt  # Remove a file
 rm -rf /path/to/dir  # Remove a directory recursively

2. File Viewing and Editing

cat: Concatenate and display file content.
```
 cat file.txt  # Display file content
```
less or more: View large files one screen at a time.
```
 less largefile.log  # View large files
```

grep: Search for a pattern within files.

 grep "pattern" file.txt  # Search for a pattern in a file
 grep -r "pattern" /path  # Recursively search in a directory

nano, vi, vim: Text editors for editing files.

 nano file.txt  # Open file in nano editor
 vi file.txt  # Open file in vi editor

3. System Monitoring and Process Management

top: Display real-time system information, including running processes.
```
 top  # Display running processes and system information
```
htop: An enhanced version of top (requires installation).
ps: Display information about running processes.
```
 ps aux  # List all running processes
```

kill: Terminate a process.

 kill -9 PID  # Forcefully terminate a process with the specified PID

df: Show disk space usage.

 df -h  # Show disk space usage in human-readable format

du: Show directory space usage.

 du -sh /path/to/dir  # Show size of a directory

4. Networking

ifconfig or ip: Display or configure network interfaces.

 ifconfig  # Display network interface information
 ip addr  # Display IP addresses

ping: Test network connectivity.

 ping google.com  # Ping Google to test connectivity

netstat: Network statistics and connections.

 netstat -tuln  # List all listening ports

curl: Transfer data from or to a server.

 curl http://example.com  # Fetch a web page

wget: Download files from the web.

 wget http://example.com/file.zip  # Download a file

5. User and Permissions Management

sudo: Execute a command as another user, typically root.

 sudo command  # Run a command with elevated privileges

chmod: Change file or directory permissions.

 chmod 755 file.sh  # Set file permissions

chown: Change file or directory ownership.

 chown user:group file.txt  # Change owner and group of a file

useradd / userdel: Add or delete a user.

 sudo useradd username  # Add a new user
 sudo userdel username  # Delete a user

passwd: Change a user’s password.

 passwd username  # Change password for a user

6. Archiving and Compression

tar: Archive files.

 tar -cvf archive.tar /path/to/dir  # Create a tar archive
 tar -xvf archive.tar  # Extract a tar archive

zip / unzip: Compress or decompress files.

 zip archive.zip file.txt  # Compress a file into a zip archive
 unzip archive.zip  # Extract files from a zip archive

7. Package Management

apt (Debian/Ubuntu): Install, update, and manage packages.

 sudo apt update  # Update package list
 sudo apt install package_name  # Install a package

yum (RHEL/CentOS): Similar to apt for Red Hat-based distributions.
```
 sudo yum install package_name  # Install a package
```

8. Automation and Scripting

cron: Schedule periodic tasks.
```
 crontab -e  # Edit the cron jobs
```
bash: Shell scripting.
```
 #!/bin/bash
 echo "Hello, World!"
```

9. Version Control (Git)

git clone: Clone a repository.

 git clone https://github.com/user/repo.git  # Clone a git repository

git pull: Update local repository with remote changes.

 git pull origin main  # Pull latest changes from the main branch

git commit: Commit changes to the repository.

 git add .  # Stage all changes
 git commit -m "Commit message"  # Commit changes

10. Docker and Kubernetes

docker ps: List running containers.
docker images: List images.
docker build: Build an image.
kubectl get pods: List Kubernetes pods.
kubectl apply -f: Apply a configuration file.

These commands cover the basics for managing a Linux environment, handling files, processes, networking, and working with popular DevOps tools like Git, Docker, and Kubernetes.

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