Bash basename syntax

Question

I'm trying to write a script that takes the basename of an argument, then checks if there is an extension in that argument. If there is, it prints the extension.

Here is my code:

file=basename $1
ext=${file%*}
echo ${file#"$stub"}
echo $basename $1

I'm echoing the final $basename $1 to check what the output of basename is.

Some tests reveal:

testfile.sh one.two
./testfile: line 2: one.two: command not found
one.two

testfile.sh ../tester
./testfile: line 2: ../tester: No such file or directory
../tester

So neither $basename $1 are working. I know it's a syntax error so could someone explain what I'm doing wrong?

EDIT:

I've solved my problem now with:

file=$(basename "$1" )
stub=${file%.*}
echo ${file#"$stub"}

Which reduces my argument to a basename, thank you all.

Answer 1

First, your syntax is wrong:

file=$( basename "$1" )

Second, this is the correct expression to get the file name's (last) extension:

ext=${file##*.}