Bash script - photo re-sizer

[jonathanku]

Hi folks, I'm struggling to get this script to work. It all works I think, except the line that tries to determine if a file begins with a certain string (i.e. "web-" without the quotes):


echo Photo re-size script \(800px max\)
echo $PWD

for img in *.JPG # for every JPG in the directory
do
echo
echo \$img: $img # output file name
if [ -f web-$img ] # check if a "web-" version of this file already exists
then
echo web-$img already exists
elif [[ $img == "web-.*" ]] # check if this file begins with "web-" so that we don't convert a converted file
then
echo File $img has already been converted
else # otherwise convert the file and prefix with "web-"
convert -resize 800x800 $img web-$img
echo $img resized
fi
done


This line is the problem: elif [[ $img == "web-.*" ]]

Any thoughts? I'm thinking that regular expression might be required.
JK

[Cracauer]

elif [[ $img == "web-.*" ]]

==>



case "$img"
in
web-*) doonething;;
*) dosometrhingelse;;
esac


I also think you misplaced the dot and the star

[jonathanku]

OK - thanks. The dot and the star was an attempt at regex <any character><zero or more times>.

Not used case before ...funny syntax with the two semi-colons.

I'll try this when I'm next at the PC. Cheers.

[ghostdog74]

what wrong with specifying "web-" in your for loop?


for img in web-*.JPG
do
...
done

[Cracauer]

I'll try this when I'm next at the PC. Cheers.

That's a pretty funny statement :)

BTW, there are no regular expressions anywhere in bourne shell syntax.

[jonathanku]

what wrong with specifying "web-" in your for loop?I'm not trying to operate on files with "web-" - I'm trying to ignore them.

BTW, there are no regular expressions anywhere in bourne shell syntax.Is bourne shell what I'm using.?! :?

[jonathanku]

elif [[ $img == "web-.*" ]]

==>



case "$img"
in
web-*) doonething;;
*) dosometrhingelse;;
esac


I also think you misplaced the dot and the star
So now I'm struggling to get this case statement to meld with my other requirements.

With the if-loop, I was also checking whether there was a web- version of the file in question.... and I don't know if that can be done with a case statement.
i.e. three checks in total :
For this file, e.g. file1.jpg, does web-file1.jpg exist For this file, does its name begin with "web-" If neither of the above, convert this jpg and prefix it with "web-"


I'm thinking there must be a simple way to determine if the first four characters in a variable are "web-".... no?


Ha---- hang on... I think I've got it... if statement first to check point 1, then case statement to deal with 2 and 3. I'll be back.

[jonathanku]

Works! Thanks.
clear
echo Photo re-size script \(800px max\)
echo $PWD

for img in *.JPG
do
echo \$img: $img
if [ -f web-$img ]
then
echo web-$img already exists
else
case "$img"
in
web-*) echo this file is already converted;;
*) convert -resize 800x800 $img web-$img;;
esac
fi
done

echo
One last question, any ideas how to say
for img in *.jpg or *.JPG ?

[ghostdog74]

I'm not trying to operate on files with "web-" - I'm trying to ignore them.
then try the find command


find . \( ! -name "web*.jpg" -a -name "*.jpg" \) | while read FILE
do
# do something with $FILE
done

[Cracauer]

One last question, any ideas how to say
for img in *.jpg or *.JPG ?

This is a problem in sh, actually.

If you say
for file in *.jpg *.JPG ; do ...

then you'll get *.JPG inserted as a token for no file that exists. Stupid. And you still miss *.JpG files.

Either use find as indicated in the last post or like this
for file in `find . -iname \*.jpg \! -name web-\*` ; do ...

Or you do it like this:
for file in *.jpg *.JPG ; do ...
test -f "$file" || continue # skip junk inserted

When we did so far isn't safe when you have space in filenames, BTW.

[jonathanku]

My Unix friend at work helped with this.... all I needed was

for img in *.[jJ][pP][gG]

So anything within the square brackets is OR-ed.