You have now seen four different types of sed scripts, as well as how
they are embedded inside shell scripts to create easy-to-use applications.
More and more, as you work with sed, you will develop
methods for creating and testing sed scripts. You will come
to rely upon these methods and gain confidence
that you know what your script is doing and why.
Here are a few tips:
Know Thy Input!
Carefully examine your input
file, using grep
, before designing your script.
Sample Before Buying.
Start with a small sample
of occurrences in a test file. Run your script on the sample and make
sure the script is working. Remember, it's just as important to make
sure the script doesn't
work where you
want it to. Then increase the size of the
sample. Try to increase the complexity of the input.
Think Before Doing.
Work carefully, testing each
command that you add to a script. Compare the output against the
input file to see what has changed. Prove to yourself that your
script is complete. Your script may work perfectly, based on your
assumptions of what is in the input file, but your assumptions may be
Try to accomplish what you can with
your sed script, but it doesn't have to do 100 percent of the job. If
you encounter difficult situations, check and see how frequently they
occur. Sometimes it's better to do a few remaining edits manually.
As you gain experience, add your own "scripting tips" to this list.
You will also find that these tips apply equally well when
working with awk.