Book Image

CentOS Quick Start Guide

By : Shiwang Kalkhanda
Book Image

CentOS Quick Start Guide

By: Shiwang Kalkhanda

Overview of this book

Linux kernel development has been the worlds largest collaborative project to date. With this practical guide, you will learn Linux through one of its most popular and stable distributions. This book will introduce you to essential Linux skills using CentOS 7. It describes how a Linux system is organized, and will introduce you to key command-line concepts you can practice on your own. It will guide you in performing basic system administration tasks and day-to-day operations in a Linux environment. You will learn core system administration skills for managing a system running CentOS 7 or a similar operating system, such as RHEL 7, Scientific Linux, and Oracle Linux. You will be able to perform installation, establish network connectivity and user and process management, modify file permissions, manage text files using the command line, and implement basic security administration after covering this book. By the end of this book, you will have a solid understanding of working with Linux using the command line.
Table of Contents (11 chapters)

Using grep for text matching

Grep (short for Global Regular Expression Print) is a command that is used extensively to as a text search tool in text files. It searches for a pattern in a file and prints the corresponding line, which contains the matching pattern. It scans files for specified patterns and can be used with regular expressions, as well as text strings. Its syntax is as follows:

$ grep [options] pattern [files]

The following table demonstrates when the grep command is used:



grep 'student' /etc/passwd

Search for a string, student, in a file, /etc/passwd, and print all matching lines

grep -v 'student' /etc/passwd

Print all lines that do not contain the string student

grep -i 'STUDENT' /etc/passwd

Search for a string, STUDENT, in a case-insensitive manner and print all matching lines (-i ignore case...