string to integer

[Javier Montoya]

Dear all,

I have a several directories with *.jpg images. The image files are
named as ascending numbers and I would like to retrieve the lowest and
largest image number in each directory. An example of the content of a
directory is given below:
/bla/bla/bla/dir1
-> 00000.jpg
-> 00001.jpg
->
-> 09001.jpg

The desired output would be the integer numbers: 0 and 9001
With the code below, I'm able to retrieve in "seqInterval" array,
which is the lowest and largest image number as strings.
seqDir="/bla/bla/bla/dir1"
seqInterval=($(find $seqDir -name "*.jpg" | sort | sed -n -e '1p;$p' |
sed -e 's|^.*/||' -e 's/\.[^.]*$//'))
in our example, I obtain sth. like:
seqInterval[0] is equal to "00000" and seqInterval[1] is equal to
"09001"
Since those are string numbers, I was wondering which is the best way
to convert those strings into integer numbers (seqInterval[0]=0 and
seqInterval[1]=9001)?

I tried the code below, but it doesn't work properly, any suggestions?
startImg=$(printf '%d' ${seqInterval[0]})
endImg=$((printf '%d' ${seqInterval[1]}))

Best whishes