Extract filename and extension in Bash

First, get file name without the path:

filename=$(basename -- "$fullfile")
extension="${filename##*.}"
filename="${filename%.*}"

Alternatively, you can focus on the last '/' of the path instead of the '.' which should work even if you have unpredictable file extensions:

filename="${fullfile##*/}"

You may want to check the documentation :

• On the web at section "3.5.3 Shell Parameter Expansion"
• In the bash manpage at section called "Parameter Expansion"

~% FILE="example.tar.gz"

~% echo "${FILE%%.*}"
example

~% echo "${FILE%.*}"
example.tar

~% echo "${FILE#*.}"
tar.gz

~% echo "${FILE##*.}"
gz

For more details, see shell parameter expansion in the Bash manual.

Usually you already know the extension, so you might wish to use:

basename filename .extension

for example:

basename /path/to/dir/filename.txt .txt

and we get

filename