Shell Programming for Systems Administrators

5 Day Course
Hands On
Code SA-245

This course has been retired. The UNIX Shell Programming course is recommended as a possible alternative.

Modules

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UNIX Shells and Shell Scripts (4 topics)

  • Describe the role of shells in the UNIX environment
  • Describe the standard shells
  • Define the components of a shell script
  • Write a simple shell script

Writing and Debugging Scripts (5 topics)

  • Start a script with #!
  • Put comments in a script
  • Change permissions on a script
  • Execute a script
  • Debug a script

The Shell Environment (13 topics)

  • Use Bourne and Korn shell variables
  • Assign values to shell variables
  • Display the value of shell variables
  • Make variables available to subprocesses using the export statement
  • Display the value of environment variables
  • Unset shell and environment variables
  • Customize the user environment using the .profile file
  • Perform arithmetic operations
  • Create and use aliases
  • Display aliases and the values assigned to them
  • Define the built-in aliases
  • Customize the Bourne and Korn shell environments
  • Use the tilde expansion and command substitution features of the Korn shell

Regular Expressions and the grep Command (4 topics)

  • Use and describe regular expressions
  • Describe the grep command
  • Use the grep command to find patterns in a file
  • Use the regular expression characters with the grep command

The sed Editor (2 topics)

  • Use the sed editor to perform noninteractive editing tasks
  • Use regular expression characters with the sed command

The nawk Programming Language (3 topics)

  • Use nawk commands from the command line
  • Write simple nawk programs to generate data reports from text files
  • Write simple nawk programs to generate numeric and text reports from text files

Conditionals (9 topics)

  • Use the exit status of a command as conditional control
  • Use the "if" statement to test a condition
  • Pass values using command-line arguments (positional parameters) into a script
  • Create USAGE messages
  • Place parameters on the command line
  • Use conditional if, then, elif, else, and fi constructs
  • Use exit, let, and test statements ([[ ]], " ")
  • Apply the &&, , and ! Boolean logic operators
  • Use the case statement

Interactive Scripts (6 topics)

  • Use the print and echo commands to display text
  • Use the read command to interactively assign data to a shell variable
  • Read user input into one or more variables, using one read statement
  • Use special characters, with print and echo, to make the displayed text more user friendly
  • Create a "here" document
  • Use file descriptors to read from and write to multiple files

Loops (4 topics)

  • Write scripts that use for, while, and until loops
  • Write a script using the select statement
  • Describe when to use loops within a script
  • Generate argument lists using command, variable, and file-name substitution

Advanced Variables, Parameters, and Argument Lists (6 topics)

  • Declare strings, integers, and array variables
  • Manipulate string variables
  • Change the values of the positional parameters using the set statement within a script
  • Use Korn shell arrays
  • Set default values for parameters
  • Use the Korn shell built-in let, print, set, and typeset statements

Functions (5 topics)

  • Create user-defined functions in a shell script
  • Create, invoke, and display functions from the command line
  • Pass arguments into a function
  • Call functions from special (function) files that are saved in one or more function directories
  • Describe where functions are available for use

Traps (3 topics)

  • Describe how the trap statement works
  • Include trap statements in a script
  • Use the trap statement to catch signals and handle errors

Prerequisites

To succeed fully in this course, students should be able to: - Use basic UNIX commands, such as rm, cp, man, more, mkdir, ps, and chmod - Create and edit text files in vi or a text editor Note: These skills are typically acquired through attendance in the SA-119 and SA-239 courses

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