Table of Contents for
Linux Shell Scripting Bootcamp

Version ebook / Retour

Cover image for bash Cookbook, 2nd Edition Linux Shell Scripting Bootcamp by James Kent Lewis Published by Packt Publishing, 2017
  1. Cover
  2. Table of Contents
  3. Linux Shell Scripting Bootcamp
  4. Linux Shell Scripting Bootcamp
  5. Credits
  6. About the Author
  7. Acknowledgement
  8. About the Reviewer
  9. www.PacktPub.com
  10. Customer Feedback
  11. Preface
  12. What you need for this book
  13. Who this book is for
  14. Conventions
  15. Reader feedback
  16. Customer support
  17. 1. Getting Started with Shell Scripting
  18. Demonstrating the use of scripts
  19. Summary
  20. 2. Working with Variables
  21. Validating parameters using conditional statements
  22. Comparison operators for strings
  23. Environment variables
  24. Summary
  25. 3. Using Loops and the sleep Command
  26. Screen manipulation
  27. Indenting your code
  28. Using the for statement
  29. Leaving a loop early
  30. The sleep command
  31. Watching a process
  32. Creating numbered backup files
  33. Summary
  34. 4. Creating and Calling Subroutines
  35. File redirection
  36. Command piping
  37. Subroutines
  38. Using parameters
  39. Making a current backup of your work
  40. Summary
  41. 5. Creating Interactive Scripts
  42. Summary
  43. 6. Automating Tasks with Scripts
  44. Summary
  45. 7. Working with Files
  46. Reading files
  47. Reading and writing files
  48. Reading and writing files interactively
  49. File checksums
  50. File encryption
  51. Summary
  52. 8. Working with wget and curl
  53. wget and recursion
  54. wget options
  55. curl
  56. Summary
  57. 9. Debugging Scripts
  58. Automatic backups
  59. More syntax errors
  60. Logic errors
  61. Using set to debug scripts
  62. Summary
  63. 10. Scripting Best Practices
  64. ssh and scp
  65. Find and use a good text editor
  66. Environment variables and aliases
  67. ssh prompt
  68. Testing an archive
  69. Progress indicator
  70. Creating new commands from a template
  71. Alerting the user
  72. Summary
  73. Index

Using the for statement

Another way to loop is to use the for statement. It is commonly used when working with files and other lists. The general syntax of a for loop is as follows:

 for variable in list
 do
     some commands
 done

The list can be a collection of strings, or a filename wildcard, and so on. We can take a look at this in the example given in the next section.

Chapter 3 - Script 7

#!/bin/sh
#
# 5/4/2017
#
echo "script7 - Linux Scripting Book"

for i in jkl.c bob Linux "Hello there" 1 2 3
do
 echo -n "$i "
done

for i in script*             # returns the scripts in this directory
do
 echo $i
done

echo "End of script7"
exit 0

And the output on my system. This is my chap3 directory:

Chapter 3 - Script 7

The next script shows how the for statement can be used with files:

Chapter 3 - Script 8

#!/bin/sh
#
# 5/3/2017
#
echo "script8 - Linux Scripting Book"

if [ $# -eq 0 ] ; then
 echo "Please enter at least 1 parameter."
 exit 255
fi

for i in $*                  # the "$*" returns every parameter given 
do                           # to the script
 echo -n "$i "
done

echo ""                      # carriage return
echo "End of script8"

exit 0

The following is the output:

Chapter 3 - Script 8

There are a few other things you can do with the for statement, consult the man page of Bash for more information.