The Shell Scripting Tutorial


Wildcards are really nothing new if you have used Unix at all before.
It is not necessarily obvious how they are useful in shell scripts though. This section is really just to get the old grey cells thinking how things look when you're in a shell script - predicting what the effect of using different syntaxes are. This will be used later on, particularly in the Loops section.
Think first how you would copy all the files from /tmp/a into /tmp/b. All the .txt files? All the .html files?
Hopefully you will have come up with:

$ cp /tmp/a/* /tmp/b/
cp /tmp/a/*.txt /tmp/b/
cp /tmp/a/*.html /tmp/b/
Now how would you list the files in /tmp/a/ without using ls /tmp/a/?
How about echo /tmp/a/*? What are the two key differences between this and the ls output? How can this be useful? Or a hinderance?
How could you rename all .txt files to .bak? Note that
$ mv *.txt *.bak

will not have the desired effect; think about how this gets expanded by the shell before it is passed to mv. Try this using echo instead of mv if this helps.
We will look into this further later on, as it uses a few concepts not yet covered.

  Previous: Variables (Part 1)  Next: Escape Characters   

My Paperbacks and eBooks

My Shell Scripting books, available in Paperback and eBook formats. This tutorial is more of a general introduction to Shell Scripting, the longer Shell Scripting: Expert Recipes for Linux, Bash and more book covers every aspect of Bash in detail.

Shell Scripting Tutorial

Shell Scripting Tutorial
is this tutorial, in 88-page Paperback and eBook formats. Convenient to read on the go, and in paperback format good to keep by your desk as an ever-present companion.

Also available in PDF form from Gumroad:Get this tutorial as a PDF
Shell Scripting: Expert Recipes for Linux, Bash and more

Shell Scripting: Expert Recipes for Linux, Bash and more
is my 564-page book on Shell Scripting. The first half covers all of the features of the shell in every detail; the second half has real-world shell scripts, organised by topic, along with detailed discussion of each script.