Faster way to extract file name

Working with unix shell and no way you wont end up extracting file names from paths. Well there is a usual way to do it.

>basename /my/big/long/path/to/a/little/bitty/file
file

Here is another way:

f1=/my/big/long/path/to/a/little/bitty/file
f2=./my/big/long/path/to/a/little/bitty/file
f3=my/big/long/path/to/a/little/bitty/file
f4=file

echo ${f1##*/}
echo ${f2##*/}
echo ${f3##*/}
echo ${f4##*/}

# This is how you get value out
filename=${f1##*/}

Output

file
file
file
file

Small Caveat

Above soln. gives slight different result than basename when the path name is a directory that ends in ‘/’. basename /my/big/long/path/to/a/little/bitty/ outputs bitty whereas above outputs nothing.

>basename /my/big/long/path/to/a/little/bitty/
bitty
>f1=/my/big/long/path/to/a/little/bitty/
>echo ${f1##*/}

>

But then, if you are trying to extract file name then /my/big/long/path/to/a/little/bitty/ should return nothing as there is no filename in the path. So logically my solution is correct.

You can use basename but that will be slow as it will launch a new child process. I can have some performance comparison but I ll leave that for later….when I get a chance. But its no-brainer that you ll get great boost in performance if you are extracting file name in a tight loop.