Beginning the Linux Command Line
Contents at a Glance
Contents
About the Author
Introduction
Chapter 1: Starting Linux Command-Line Administration
Linux Distributions
Linux History
Open Source
The First Distributions
Linux Turning Mainstream
Red Hat
SUSE
Ubuntu
Logging In and Out
Different Login Interfaces
Working with a User Account
Command-Line Basics
Bash: The Command Interpreter
Commands, Options, and Arguments
Options
Arguments
Piping and Redirection
Piping
Redirection
Getting Help
Using man to Get Help
man Sections
Using the --help Option
Getting Information on Installed Packages
Working with the Shell
Using the Shell to Best Effect
Working with Files and Directories
Using automatic Command Completion
Working with Variables
Working with Bash history
Managing Bash with Key Sequences
Summary
Chapter 2: Performing Essential Command‑Line tasks
Changing Your Password
Working with Virtual Consoles
Becoming Another User
Obtaining Information About Other Users
Communicating with Other Users
Real-Time Communication
Individual Chat Sessions with write
Writing to all Users
Disabling Real‑Time Messages
Sending Mail from the Command Line
Finding Your Way in the File System
Default Directories
Working with the Linux File System
Working with Directories
Working with Files
Listing Files with ls
Removing Files with rm
Copying Files with cp
Moving Files with mv
Cool Commands
Displaying a Calendar with cal
Clearing Your Screen with clear
Displaying System Information with uname and hostname
Counting Words, Lines, and Characters with wc
Changing and Showing Date and Time with date
Summary
Chapter 3: Administering the Linux File System
Mounting Disks
Using the mount Command
Options for the mount Command
Getting an Overview of Mounted Devices
Unmounting Devices
Automating Mounts with /etc/fstab
Checking File System Integrity
Creating Backups
Making File Backups with tar
Creating an Archive File
Path Names in tar
Extracting an Archive File
Moving a Complete Directory
Creating Incremental Backups
Making Device Backups Using dd
Working with Links
Why Use Links ?
Working with Symbolic Links
Understanding Inodes
Understanding the Differences Between hard and Symbolic Links
Working with Hard Links
Links Recap
Summary
Chapter 4: Working with Text Files
Working with Vi
Vi Modes
Saving and Quitting
Cutting, Copying, and Pasting
Deleting Text
Moving Through Text Files
Changing All Occurrences of a String in a Text File
Vi Summarized
Displaying Contents of Text Files
Showing File Contents with cat and tac
Showing a File’s Last Lines with tail
Displaying the First Lines in a File with head
Browsing File Contents with less and more
Cool Text File Manipulation Tools
Changing Contents in a Batch with tr
Sorting Text Files with sort
Finding Differences Between Text Files with diff
Checking Whether a Line Exists Twice with uniq
Getting Specific Information with cut
Advanced Text File Filtering and Processing
Working with Basic Regular Expressions
Working with Programmable Filters
Working with sed
Manipulating text Files with awk
Printing Files
Managing CUPS Print Queues
Creating Print Jobs
Tuning Print Jobs
Removing Print Jobs
Finding Files
Summary
Chapter 5: Managing Partitions and Logical Volumes
Addressing Storage Devices
File System Labels
udev Device Names
Working with UUID
Creating Partitions
Understanding Partitions
Understanding MBR and GPT Disks
Creating MBR Partitions
Managing Partitions with fdisk
Creating Partitions
Telling the Kernel about the New Partitions
Deleting Partitions
Fixing the Partition Order
Creating GPT Partitions with gdisk
Working with cfdisk
Recovering Lost Partitions with gpart
Creating Logical Volumes
Understanding Logical Volumes
Setting Up a Disk with Logical Volume Manager
Creating Physical Volumes
Creating Volume Groups
Creating Logical Volumes
Working with Snapshots
Basic LVM Troubleshooting
Working with File Systems
Understanding File Systems
About Inodes and Directories
About Superblocks, Inode Bitmaps, and Block Bitmaps
Journaling
Indexing
Btrfs
Btrfs Tools and Features
Understanding Subvolumes
Working with multiple devices in Btrfs
Formatting File Systems
Maintaining File Systems
Analyzing and Repairing Ext
Analyzing and Repairing XFS File Systems
Resizing File Systems
Resizing a File System in a Logical Volume
Resizing Partitions with GParted
Working with Windows File Systems
Cloning Devices
Summary
Chapter 6: Managing Users and Groups
Setting Up User Accounts
Understanding Users and Their Properties
Username
Password
UID
Group Membership
Gecos Field
Home Directory
Shell
Commands for User Management
Working with Default Values for User Management
Setting Default Values Using /etc/default/useradd
Creating a Default environment Using /etc/login.defs
Managing Passwords
Performing Account Maintenance with passwd
Managing Password Expiration
Behind the Commands: Configuration Files
/etc/ passwd
/etc/ shadow
Group Membership
Creating Groups
Commands for Group Management
Behind the Commands: /etc/group
The Use of Group Passwords
Managing the User’s Shell Environment
Creating Shell Login Scripts
Showing Messages to Users Logging In
Applying Quota to Allow a Maximum Amount of Files
Installing the Quota Software
Preparing the File System for Quota
Initializing Quota
Setting Quota for Users and Groups
Techniques Behind Authentication
Understanding Pluggable Authentication Modules
Discovering PAM Modules
pam_deny
pam_env
pam_limits
pam_mail
pam_mkhomedir
pam_nologin
pam_permit
pam_rootok
pam_securetty
pam_tally
pam_ time
pam_unix
pam_warn
The role of /etc/nsswitch.conf
Configuring Administrator Tasks with sudo
Summary
Chapter 7: Managing Permissions
Setting Ownership
Displaying Ownership
Changing User Ownership
Changing Group Ownership
Default Ownership
Basic Permissions: Read, Write, and Execute
Understanding Read, Write, and Execute Permissions
Applying Read, Write, and Execute Permissions
Advanced Permissions
Understanding Advanced Permissions
Applying Advanced Permissions
Working with Access Control Lists
Understanding ACLs
Preparing Your File System for ACLs
Changing and Viewing ACL Settings with setfacl and getfacl
Setting Default Permissions with umask
Working with Attributes
Summary
Chapter 8: Managing Software
Understanding Software Management
Managing RPM Packages
Working with RPM
Working with yum
Managing yum Repositories
Managing Software Packages with yum
Working with zypper
Managing zypper Software Repositories
Managing RPM Packages with zypper
Managing DEB Packages
Managing .deb Software Repositories
Ubuntu Package Management Utilities
Understanding apt
Showing a List of Installed Packages
Using aptitude
Adding and Removing Software with apt-get
Summary
Chapter 9: Process and System Management
Understanding Linux Processes
Monitoring Processes
Monitoring Processes with top
Finding Processes with ps
Finding PIDs with pgrep
Showing Parent-Child Relations with pstree
Managing Processes
Killing Processes with kill, pkill, and killall
Killing processes with kill
Killing processes with killall
Killing processes with pkill
Adjusting Process Priority with nice
Process Management from top
Scheduling Processes
Creating user crontabs
Understanding cron.{hourly|daily|weekly|monthly}
Using /etc/cron.d
Summary
Chapter 10: System Logging
Understanding Logging
Monitoring Files in /var/log
Configuring the syslog Service
Configuring syslog-ng
Sending Logs Yourself with logger
Rotating Old Log Files
Understanding Journald
Summary
Chapter 11: Configuring the Network
A Quick Introduction to Computer Networking
Understanding Network Device Naming
Setting the IP Address
Using the ip Tool
Showing Ip addresses with ip
Showing Device attributes
Setting the IP address
Using ifconfig
Displaying Information with ifconfig
Configuring a Network Card with ifconfig
Bringing Interfaces Up and Down with ifconfig
Using Virtual Ip addresses with ifconfig
Storing Address Configuration
Storing IP Address Configuration on Ubuntu
Storing IP Address Configuration on Red Hat
Storing IP Address Configuration on SUSE
Configuring Routing
Managing the Default Route with route
Managing the Default Route with the ip Tool
Storing Routing Information
Ubuntu
Red Hat
Resolving DNS Names to IP Addresses
The Role of the /etc/nsswitch.conf File
Using the /etc/hosts File
Tuning the Network Card with ethtool
Analyzing Network Connections
Testing Connectivity
Testing Routing
Testing Availability of Services
Using netstat for Services on Your Computer
Using nmap to Check Services on remote Computers
Connecting Remotely with Secure Shell
Working with Public/Private Key Pairs
Working with Secure Shell
Using the ssh Command
Using scp to Copy Files Securely
Using sftp for Secured Ftp Sessions
Configuring SSH
Using SSH Key-Based Authentication
A Short Introduction To Cryptography
Using P ublic/Private Key–Based Authentication in an SSh Environment
Setting Up SSh for Key-Based Authentication
Caching Keys with ssh - ssh-agent
Tunneling Traffic with SSH
X Forwarding
Generic tCp port Forwarding
Summary
Chapter 12: Configuring a File Server
Operating File Servers Securely
Creating a Samba File Server
Background of the Samba Project
Configuring a Samba File Server
Configuring the Share
Creating the User Account
Starting Samba Services
Working with additional parameters in smb.conf
Accessing a Samba File Server
Accessing Samba from the Command Line
Configuring Samba Access on Booting
Basic Samba Troubleshooting
Configuring an NFS Server
NFS Backgrounds
Understanding NFS Processes
Configuring an NFS Server
Tuning the List of Exported File Systems with exports
Configuring an NFS Client
Mounting an NFS Share with the mount Command
Mounting an NFS Share automatically from fstab
Getting a List of available NFS Shares
Summary
Chapter 13: Working with the Kernel
Understanding the Kernel
Managing Kernel Modules
Listing Modules with lsmod
Loading and Unloading Modules with modprobe
Displaying Module Properties with modinfo
Changing Module Options
Managing Module Dependencies
Legacy Commands for Module Management
Finding the right Hardware Module
Tuning Kernel Parameters
Writing Changes to /proc
Some Useful /proc Parameters
Compiling Your Own Kernel and Kernel Modules
Understanding Make
Modifying and Compiling the Kernel
Modifying the Kernel
Creating a .config file from Scratch
Creating a .config Based on the Default Configuration
Compiling a New Kernel
Compiling Modules
Managing the Grub2 Bootloader
Summary
Chapter 14: Introduction to Bash Shell Scripting
Basic Shell Script Components
Elements of a Good Shell Script
Executing the Script
Making the Script Executable
Running the Script as an Argument of the bash Command
Sourcing the Script
Working with Variables and Input
Understanding Variables
Variables, Subshells, and Sourcing
Working with Script Arguments
Using Script arguments
Counting the Number of Script Arguments
Referring to all Script Arguments
Asking for Input
Using Command Substitution
Substitution Operators
Changing Variable Content with Pattern Matching
Performing Calculations
Using Control Structures
Using if ... then ... else
Case
Using while
Using until
Using for
Summary
Appendix A: Installing Linux
Installation Requirements
Installing CentOS
Installing Ubuntu Server
Index