BASH Shell Scripting and UNIX utilities

Shell scripting is one of the most used programming languages by system administrators and database administrators. Its used to automate many routine SA and DBA tasks. For any system and database administrator, knowledge of shell scripting is a added advantage. At Ahana we have a shell scripting course based on BASH and our tutors themselves were SA's and DBA's and have a very good knowledge.

What we cover

Day 1




Background and Introduction to SHELL

• What is shell
• Differnt Types of Shell, How to invoke a Shell, Which Shell we using.
• Why use Shell scripts

Getting Started

• A Simple Script and standard first line
• Building Blocks of a shell Script - Commands and Arguments, Variables, I/O Redirection, Decisions and Looping
• Execution Tracking - Simple Debugging

Text manipulation - Strings and Files

• Searching text - grep command family
• Regular Expressions - powerful string manipulation tool/language
• BRE - Basic Regular Expression
• ERE - Extended Regular Expression
• Streams Editor - sed

  Some test exercises

  
  

  Day 2

  
  

  Text Manipulation - Fields and Records

• Using "cut"
• Using "join"
• Text manipulation using awk - basics

More Text Processing tools

• Data sorting
• Use of unix utilities - sort, uniq, wc, fmt, head and tail

What are pipes

Variables

• Understanding Variables and Shell Environment
• Exporting variables to environment and setting variables readonly
• Parameter Expansion
• Expansion Operators
• POSIX Operators
• Positional parameters
• Special Variables
• Arithmetic Expansion

Some test exercises




Day 3




Exit status and exit command

Decision making

• "if-elif-else-fi"
• Logical NOT, AND and OR
• "test" command and test expression
• "case" statement

Looping

• "for" loops
• "while" and "until" loops
• "break" and "continue"
• "shift" and option processing

Functions

Some test exercises




Day 4




Input/Output, Files and Command Evaluation

• standard input, output and error
• Reading lines - "read" command
• Redirections, redirectional operators and file descriptors
• Tilde and wildcard filename expansions
• Command substitution, Quoting, Evaluation order, Shell built in commands

Working with Files

• Understanding filesystems, Directories and files
• Finding files - "find"
• Making use of "xargs"
• Useful Filesystem and file comparison utilities

Processes

• Understanding UNIX processes
• Creation and listing of processes
• Controlling and Deletion of Process
• Trapping process signals
• Note on Process Accounting
• Process scheduling - "at" and "cron"
• /proc filesystem

BASH Shell - common Extenstions

A few words on - Restricted shell, Trojan hourses and setuid/gid scripts




Q & A

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