UNIX for Dummies Questions & Answers

How do I keep a file pattern from evaluating?

I want to pass in a file pattern to a script as a parameter, and then use that pattern in subsequent statements, but I can't get the pattern to not evaluate before I use it.

For example, if I have 3 files called file1.txt, file2.txt and file3.txt and in my script I have something like this:

num=`ll $1 | wc -l`

and I pass file*.txt in as my parameter, num always = 1. Because $1 evaluates to "file1.dat file2.dat file3.dat", all one line.

So essentially my statement says

num=`ll file1.dat file2.dat file3.dat | wc -l`

How do I get it to ask:

num=`ll file*.dat | wc -l`

so that my answer will correctly be 3?

Thanks.

When you invoke your script use:

Code:

script 'file*.txt'

instead of using:

Code:

script file*.txt

Alternatively, in your script change:

Code:

num=`ll $1 | wc -l`

Code:

num=`ll "$@" | wc -l`

If you want all of the arguments passed to your script to be counted. But, I assume you have other parameters you're passing to your script or you would just use:

Code:

num=$#

which is a MUCH faster way to give you the same results.

It's also safer than trying to expand * inside your script, too.