Extract filename and extension in Bash

Question

I want to get the filename (without extension) and the extension separately.

The best solution I found so far is:

NAME=`echo \"$FILE\" | cut -d\'.\'          


        

Answer 1

That doesn't seem to work if the file has no extension, or no filename. Here is what I'm using; it only uses builtins and handles more (but not all) pathological filenames.

#!/bin/bash
for fullpath in "$@"
do
    filename="${fullpath##*/}"                      # Strip longest match of */ from start
    dir="${fullpath:0:${#fullpath} - ${#filename}}" # Substring from 0 thru pos of filename
    base="${filename%.[^.]*}"                       # Strip shortest match of . plus at least one non-dot char from end
    ext="${filename:${#base} + 1}"                  # Substring from len of base thru end
    if [[ -z "$base" && -n "$ext" ]]; then          # If we have an extension and no base, it's really the base
        base=".$ext"
        ext=""
    fi

    echo -e "$fullpath:\n\tdir  = \"$dir\"\n\tbase = \"$base\"\n\text  = \"$ext\""
done

And here are some testcases:

$ basename-and-extension.sh / /home/me/ /home/me/file /home/me/file.tar /home/me/file.tar.gz /home/me/.hidden /home/me/.hidden.tar /home/me/.. .
/:
    dir  = "/"
    base = ""
    ext  = ""
/home/me/:
    dir  = "/home/me/"
    base = ""
    ext  = ""
/home/me/file:
    dir  = "/home/me/"
    base = "file"
    ext  = ""
/home/me/file.tar:
    dir  = "/home/me/"
    base = "file"
    ext  = "tar"
/home/me/file.tar.gz:
    dir  = "/home/me/"
    base = "file.tar"
    ext  = "gz"
/home/me/.hidden:
    dir  = "/home/me/"
    base = ".hidden"
    ext  = ""
/home/me/.hidden.tar:
    dir  = "/home/me/"
    base = ".hidden"
    ext  = "tar"
/home/me/..:
    dir  = "/home/me/"
    base = ".."
    ext  = ""
.:
    dir  = ""
    base = "."
    ext  = ""