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

wget options

Normally the defaults used by wget are good enough for most users, however, you may need to tweak things from time to time to get it to work the way you want it to.

Here is a partial list of some of the wget options:

wget option

Explanation

-o filename

Output messages to a log file. This was covered earlier in the chapter.

-t number

Try number times before giving up on the connection.

-c

Continue to download a partially downloaded file from a previous wget.

-S

Display the headers sent by the server.

-Q number

The quota, or total amount of bytes that will be downloaded. Number can be in bytes, kilobytes (k), or megabytes (m). Set to 0 or inf for no quota.

-l number

This specifies the maximum recursion level. The default is 5.

-m

This is good for when trying to create a mirror of a site. It is equivalent to using the -r -N -l inf --no-remove-listing options.

Another thing you may try is to turn on debugging with the -d option. Note that this will only work if your version of wget was compiled with debug support. Let's see what happens when I try it on my system:

wget options

I wasn't sure if debugging was turned on or not, now I know. This output might not be very useful unless you are a developer, however, if you ever need to send in a bug report on wget they are going to ask for the debug output.

As you can see, wget is a very powerful program with several options.

Note

Remember to use wget with care and do not forget to put a sleep of at least a minute in your loop. An hour would be even better.