extra help with bash
 

I've been reading a lot of tutorials but cant find exactly what I want.
I want to check if there are any JPG or jpeg files before I process them with ImageMagik.
All I have found is
if [ -f filename ]
which only checks for one file, I want to check for *.JPG but using if [ -f *.JPG ] fails if more than one JPG file exists.

Keefaz big thanks, that script for identify worked well and after changing $h > 800 to $w >= $h I got rid of the portrait orientated pics as well as the small ones. It takes 10 - 15 minutes to process approx 12500 files and I can live with that especially as my box is about 7 years old.

i would do something like this:

Oops I haven't explained my problem properly. I want to make all JPG and jpeg files jpg files. At the moment I do "rename JPG jpg *.JPG" (same for jpeg) and ignore the error message when there are no files to be changed. I would much prefer to have the rename in some sort of test.

Second question is to do with tidying up the file names. The script I found uses tr so I have ended up with this bit of code

image3=`echo "$image2" | tr " " "_"`
if [ "$image3" != "$image1" ]; then
mv "$image1" "$image3"
fi

But I really would like to be able to do the test first. Anyone got any alternatives ?

I am not a sed specialist but...
(used $image1 as I don't know what $image2 is)

Looks like your sed knowledge is better than my typing ability (image2 should read image1). Still have the issue of doing the test after the change, which I was taught is bad programming.
If it helps you with sed while searching script tutorials I came across this
# badname.sh
# Delete filenames in current directory containing bad characters.

for filename in *
do
badname=`echo "$filename" | sed -n /[\+\{\;\"\\\=\?~\(\)\<\>\&\*\|\$]/p`
# badname=`echo "$filename" | sed -n '/[+{;"\=?~()<>&*|$]/p'` also works.
# Deletes files containing these nasties: + { ; " \ = ? ~ ( ) < > & * | $
#
echo "rm " "$badname"
# rm $badname 2>/dev/null
# ^^^^^^^^^^^ Error messages deep-sixed.
done

but that doesn't solve the issue of I would rather do the test for spaces (and/or other dodgy characters) before changing the file name.

Test for spaces doesn't matter as long as you just manipulate the file name
After you finish the name change, you just test with -f if file exists before doing the actual rename

PS: thanks for the sed examples, have to dig it a little more

I could get silly and say :- but, but, but, even COBOL lets you say
IF filename INCLUDES a space THEN PERFORM the change
However I know shell scripting is not compiled and therefore is limited in what can be done.
Would it be possible to write a bash function along the lines of

Function Includes(filename)
local respone = false
move filename to an array of single characters the length of filename # this line is the tricky bit
for cnt = 1 , length of filename
do
if array[cnt] = " "
then
response = true
fi
od
return response

I can see issues with the above code already, such as it probably should return true
as soon as it finds a space. More importantly if I was to write that then it would seem
sensible to change the space characters there and return the new file name and then I wouldn't
need the line with tr in it.

ps how do stop the rename getting errors?

You can do the space test more easily, bash has reg exp matching function

My other issue is I need a "move_all_but *.jpg to_somewhere_else" command. At the moment I am doing

mkdir $tmp_dir
mkdir $oth_dir
mv *.jpg $tmp_dir
mv *.* $oth_dir
mv $tmp_dir/* .
rmdir $tmp_dir

which looks really ugly to me.
Can anyone suggest a more elegant solution?

You can use bash GLOBIGNORE env variable to ignore .jpg files, something like:

then all files but jpgs are moved to $dir

since your filenames are inconsistent to me it makes better sense to use the mime-type (file -i) to figure out the actual file type.

this worx for me:

The script is getting better, processed about 30000 files in 16 minutes yesterday.
I like the idea of GLOBIGNORE.
So will have to do some more testing today.
I'm getting really really bored with two things, one - spending what seems like hours going through tutorials and not finding what I need, two Hello World !

Keefaz there is a slight bug in your GLOBIGNORE example. It needs mv *.* $dir otherwise it tries to move $dir into a subdirectory of itself.

what if the dir name is dir.name ?