Zero Padded Files

mina86 · 02-04-2013, 02:57 PM

Quote:

Originally Posted by konsolebox

Can I ask in what sense could it be more portable? What shell / version of Bash?

Portable if anyone decides to port the script to a pure POSIX shell.

PTrenholme · 02-05-2013, 09:43 PM

With a fairly minor change (in red, below) ntubski's test program works fine:

Code:

$ cat greatest
#!/bin/bash

# run this in a new directory
mkdir ./gr
pushd gr &>/dev/null
touch 000{1..8}.mp3

files=(*.mp3)
greatest=$(basename ${files[-1]%.*})
((i=10#$greatest+3))
echo "i = $i, greatest = $greatest"
popd &>/dev/null
rm -rf gr/
$ ./greatest 
i = 11, greatest = 0008

<edit>
Of course, adding the 3 is unnecessary if you explicitly set your base to ten...
</edit>

ntubski · 02-05-2013, 10:01 PM

Quote:

Originally Posted by mina86

Portable if anyone decides to port the script to a pure POSIX shell.

In which case arithmetic expressions wouldn't work at all, no?

@PTrenholme: yes, but the question is really how the original code from the first post (supposedly) worked. My guess is that jroggow didn't actually run the code they thought they were running.

mina86 · 02-06-2013, 10:50 AM

Quote:

Originally Posted by ntubski

In which case arithmetic expressions wouldn't work at all, no?

Of course they would. But yes, I was a bit haste in my explanation. The “$(($x))” meaning the same as “$((x))” statement was added in later POSIX versions as well, so a recent pure POSIX shell will also support it, but nonetheless, using dollar sign helps with portability with those slightly older pure POSIX shells.