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A man page (short for manual page) is a form of software documentation. Topics covered include computer programs (including library and system calls), formal standards and conventions, and even abstract concepts. A user may invoke a man page by issuing the man command. By default, man typically uses a terminal pager program such as more or less to display its output. man <command> - man followed by a command (for which you want help) opens manual for reading. Press q to quit the manpage. Some man pages contain examples. man -f <command> - brief overview of command man -k <search string> - shows a list of man pages containing a string. whatis <command> - Equal to man -f <command>. To see just the description of a manual page, use whatis followed by a string. whereis -m <command> - Equal to man -w <command>. The location of a manpage can be revealed with whereis. man sections - By now you will have noticed the numbers betwee

Linux File Structure  Linux has the default file structure which can be seen in below image To know about the different directories and their usage, hit the below command in your linux machine terminal man hier / - root directory where the whole tree starts. Only root user has write previleges here /bin - contains binary executables. Common commands used in single user mode are available here. Eg : ps, ls, ping, locate, zip, grep, who /boot - static boot loader files required during the boot process.   Kernel initrd, vmlinux, grub files are located here /dev - Device files which belong to ohysical devices. These include terminal devices, usb, or any device attached to the system /etc - Configuration files of the machine are present here. This also contains startup and shutdown shell scripts used to start/stop individual programs /etc/opt - host specific files of the add on softwares are present here /etc/skel - When new user is created, files from h

Basics of Operating System OS manages computer hardware and also acts as intermediary between user and hardware. Computer hardware consists of CPU, Memory and I/O Devices.  Main functions of OS are  Allocation of resources Load and manage processes Provide interface to hardware via system call Basic UI,  Provide file system  Management of memory and security etc. Types of OS are Single and Multi tasking Single and Multi User Distributed Templated (Eg., Virtual Image) Various OS available in the market are Windows MacOS Unix/Linux based. What is Linux Above picture shows main components in Linux OS such as Kernel, Sys Libs, System default softwares, User process and utility, Kernel modules etc. The main features of Linux are: Detecting and preparing hardware  Managing processes  Managing memory  Providing user interfaces Controlling filesystems Providing user access and authentication Advanced features in Linux, often used in large enterp

Chapter 1 : Introduction to Linux Basics of Operating System What is Linux Linux Distributions Installation of Linux Chapter 2 : Basics of Linux Linux File Structure What is Shell Basic Linux Commands File and Directory manipulations Find and grep Shell prompt customization Shell alias File globbing I/O redirection Pipes Comparing files Command history Man pages Environment variables Common filter commands File Permissions Editing files using Vi Editor Process control Su and sudo access control Chapter 3 : User and Group Management User Management Group management Chapter 4 : Boot Process Bootstrap process GRUB Rebooting and Shutdown Working with startup scripts Syslog and log files Chapter 5 : Software Package Management Using Kickstart for RHEL RPM and yum DEB and apt-get Chapter 6 : Storage Management Disk Storage basics Disk Partitioning Mounting concepts RAID LVM Chapter 7 : Backup and Recovery Bac

Here is the top 5 must have books for system administartors who are starting working in Unix and Linux adminstration or current system administartors who want to improve skills and go deeper to learn and manage Unix and Linux systems. 1- Unix and Linux System Administration Handbook (by Evi Nemeth, Garth Snyder, Trent R. Hein,) Targeted at beginners to intermediate levels it covers everyday system administration tasks along with storage, network , email, web hosting, scripting, software configuration management, performance analysis, Windows interoperability, virtualization, DNS, security, management of IT service organizations. 2- Essential System Administration: Tools and Techniques for Linux and Unix Administration( by Æleen Frisch) Targeted at beginners, provides hand on approach to real world by explanation and examples. Several Unix flavors such as AIX, FreeBSD, HP-UX, Solaris, Tru64 along with Linux environments are covered along with DHCP, USB devices, automation tool