# System Engineer-(Rhcsa + Rhce) ## Basic Commands / Structure * Navigating the Filesystem using linux commands * Managing files using commands (cat,find,chmod) * System Monitoring and Management * Managing and configuring Network through Commands * Package management on Red Hat-based system (yum,rpm,dnf) * File compression and archiving (tar, gzip, zip, unzip) * Ubuntu Installation Commands * Installation 3 methods * Rhel 6 7 8 9 distinguish ### Editor - Vi/Vim,Nano * Nano editor,Vi/Vim Editors * Editing files in insert mode * Understanding visual mode * Difference between vi and vim * Understanding how to Navigate around files * Command abbreviation * performing backup and recovery * opening multiple file tabs ### Runlevels * Role of runlevels in system boot and shutdown. * omparison of SysVinit and Systemd. * Rebooting the system using runlevels.. * Changing runlevels using init cmd ### Ownership & Permission * Creating and managing user accounts and their groups * Securing sensitive files and directorsie * Differences between traditional permissions and ACLs. * Symbolic notation (Reading and interpreting permission symbols). * Implementing least privilege for users and groups. * Troubleshooting Permissions Issues. ### Find/Locate/Grep FIND * Basic File Searching with find * Searching by file type (directories,regular files and Filtering) * Advanced File Searching with find Locate * Locating Files with locate * Limiting search to specific directories,Filtering search results * Executing commands on search results Grep * Searching Inside Files with grep(Searching for text patterns,searching in multiple files,searching in different files) * Recursive searching in directories * Searching system logs (finding error messages,filtering log entries) ### Backup Folders and Files Using Cp,mv and Rsync * Copying multiple files and directories Using Cp command * Backing up data to external storage Using Rsync * Synchronizing directories (Local and remote synchronization.) * Handling large directory structures efficiently Using Mv Command * Migrating data between disks or partitions. ### FSH - File System Hierarchy * Understanding the root directory (/):Role and significance,Root directory structure. * /bin and /sbin directories and differences between them * System Directories and their protocols(/-root and /tmp-temporary files storage ) * Virtual filesystems for process and system information * Understanding differences between distributions * Package management and its impact on FSH * Understanding Links and Mount Points * Differences between symbolic and hard links * Creating and managing links * Mounting and unmounting filesystem ### Symlinks & Hardlinks * Differences between hard links and symbolic (soft) links. * Advantages and use cases of hard and symbolic links * Characteristics of hard links (Shared Inode Numbers,Same Physical Files etc) * Modifying and deleting hard-linked files * Finding and fixing broken symbolic links ### Fdisk - Disk Manage * Understanding Disk Devices in Linux * Command-line options and arguments * Partitioning Disks with fdisk (Primary partitions,Extended partitions) * Partition Management with fdisk * Resizing existing partitions * Converting partition table types * persisting it in fstab ### Advance Permission * Access Control Lists (ACLs):(Setting ACLs using setfacl,Modifying and removing ACL entries,Managing default ACLs) * Extended Attributes * Understanding of changing attributes (chattr) * Setting special permissions using chmod * understanding purpose and significance of setui,setgid and sticky bit * Using default permissions and umask * Interaction between encryption and file permissions * Automating permission management tasks ### Sudoers * Location and structure of the sudoers file. * Granting sudo(root) access to a user. * Managing group-based permissions with sudo. * Understanding Cmnd\_Alias, User\_Alias, Host\_Alias, and Runas\_Alias * Restricting specific commands for users. ### Umask & Path Umask * Understanding umask notation (octal vs symbolic) * Calculating effective permissions using umask * Setting and Modifying Umask * Permanent and temporary umask changes * Calculating effective permissions using umask Path * How PATH is used to locate executable files (Absolute and relative path) * Managing the PATH Variable * Removing directories from the PATH * Setting PATH for all users and individual users * Identifying common issues related to umask and PATH * Debugging problems with umask and PATH configuration ### Process & Daemons Process * Managing Processes using (Pid) * Listing processes Using ps command * Identifying resource usage (CPU, memory, etc.) * Sending signals to processes (kill command) * Process Management and Job Control * Monitoring processes (top,htop) * Server health check * monitor server cpu memory load Daemons Daemon Management and Configuration * Using systemctl to manage systemd servic * Troubleshooting daemon startup issues * Init systems and daemon management (systemd, cron) Cron * Managing Cron Jobs Using (crontab) command * Used to run scripts * Syntax for specifying time intervals * Backing up Cron configurations * Troubleshooting Cron Issues ### Archive & Compression * File Archiving with tar and zip * Compression with gzip and bzip2 * Advanced Compression Techniques * Archive and Compression Tools Comparison * Compression Formats and Compatibility * Security implications of compression * Creating and extracting compressed archives for different use cases ### Shell Scripting * Using scripts in bash shell * Script file permissions and execution * Control Structures (if -else constructs) * Looping constructs (for-loop,while-loop) * File and Directory Handling * String Manipulation * Concatenation and substrings * Error Handling and Debugging * Using pipes to connect commands ### Networking * Configuring Network Interfaces (ifconfig,ip command) * Configuring network settings in linux files * Automating and Managing Network Connections * Configuring DNS servers * Configuring hostname resolution * Understanding network routing concepts * Configuring hostname resolution * Understanding NAT concepts * Network Monitoring and Troubleshooting * Troubleshooting Hostname /etc/hosts , /etc/resolv.conf * Gateway,Routes,Subnets,Aliasing ### Ports & Protocol * Understanding Ports and Protocols * Common network protocols (TCP, UDP, ICMP, etc.) * Network troubleshooting and diagnostics * Port Scanning and Services Identification * Security considerations when opening ports * Common network services and their default ports (e.g., SSH, HTTP, FTP) ### Rpm * Components of an RPM package * RPM Package Management * Querying RPM Packages * Setting up a RPM build environment * RPM package scripting * Creating RPM package repositories * Features and advantages of yum over traditional package ### Yum * Features and advantages of yum over traditional package management methods * Installing and removing packages with yum * Configuring yum repositories * Resolving dependency issues with yum * Advanced yum Commands * Understanding yum configuration files * Troubleshooting with yum * Automating package installations and updates with yum ### Lvm * LVM Components - (Physical Volumes (PV), Volume Groups (VG) Logical Volumes (LV) * Configuring Physical Volumes (PV) * Creating Volume Groups (VG) - (Modifying volume groups (resizing, adding/removing physical volumes) * LVM and Disk Management- (Moving logical volumes between volume groups, Splitting and merging volume groups) * Resizing Logical Volumes - (Extending LVs: lvextend, Reducing LVs: lvreduce) * Adding Disks with VolumeGroup * Lvm Remove Pv(Physical Volume),vg(Volume Group),Lv(Logical Volume).
* User Management * Types of Users (System Users, Regular User, Root User and Superuser Privileges) * User and Group Identifiers- (UID (User ID) and GID (Group ID) * Adding and Deleting Users * Modifying User Accounts * Managing User PasswordM * Understanding Groups - (Primary and Secondary Groups) * Advance permissions - (SUID, SGID, STICKY BIT) ### Boot Process * BIOS/UEFI Initialization * Configuration files for boot loaders * Kernel initialization process * Kernel parameters and their significance * Service management and dependency resolution * Troubleshooting GRUB configuration errors * Recovery options and rescue environments * Analyzing boot logs and diagnosing boot issues ### Troubleshooting * Kernel Boot Problems-(Kernel Panics,Rescue mode) * Bootloader Issues - (GRUB Configuration) * Filesystem Errors and Repair - (Identifying Disk Issues Checking and Repairing Filesystems: fsck) * Ctrl D Maintenence Mode ### Selinux * Understanding SELinux policies * SELinux Configuration * SELinux Troubleshooting * SELinux Modes - (Enforcing, Permissive, and Disabled) * SELinux Policies-(Targeted, Minimum, MLS (Multi-Level Security) * Key Components and Configuration Files. * Configuration in files permission ### Ntp * Basics of time synchronization * NTP operation modes(Client mode,Server mode) * Managing NTP service * High Availability and Redundancy * Starting and Stopping NTP Service * Monitoring NTP Service (NTP Queries: ntpq, ntpstat) ### SSH * Installing and Configuring SSH * Connecting to Remote Systems * SSH Key Management- (Generating SSH Keys: ssh-keygen, Copying Public Keys to Remote Systems) * Enhancing SSH Security - (Disabling Root Login, Configuring AllowUsers and DenyUsers) ### Ansible Basic * Ansible Configuration * Running ad-hoc commands with Ansible * Ansible Modules * Variable precedence * Playbook Execution and Testing * Ansible Playbooks (10 Playbooks) * Working with YAML * Securing Ansible control node and managed nodes * Limiting access to Ansible control node * Securing sensitive data in playbooksM * Hosts and groups configurations * Inventory file for Multiple Servers * Creating and using roles in Ansible playbooks * Encrypting and decrypting files with Ansible Vault * Ansible Galaxy * Organizing playbooks using roles * Ansible Roles and Handlers ### NFS * Implement Network file Sharing * Granting permisson to clients * Mounting from Linux Client * Mount Persistent * Rpc Access ### FTP * File transfer protocol * Installing Vsftpd Service * Accessing files from client ftp-browser * Granting permisson to Ftp * Active-Passive Ftp