Exclude file names with a specific prefix in the for (globbing) loop

Question

This is probably pretty easy, but I can't figure it out. In the for loop, I want to exclude certain files with a prefix zz(for example, zz131232.JPG), but I do not know how to exclude these files.

for i in *.JPG; do
    # do something
done

How to change the rule "for rule" to exclude files with a prefix zz?

Answer 1

Sort of

for i in *.JPG; do
  [[ $i != "zz"* ]] && echo "$i"
done

or skip them:

for i in *.JPG; do
  [[ $i == "zz"* ]] && continue
  # process the other files here
done

Answer 2

If you are dealing with many files, you can also use GLOBIGNOREor extended globbingto avoid expanding the files you want to skip in the first place (which can be faster):

GLOBIGNORE='zz*'
for file in *.JPG; do
    do_something_with "${file}"
done
# save and restore GLOBIGNORE if necessary

or

shopt -s extglob # enable extended globbing
for file in !(zz*).JPG; do
    do_something_with "${file}"
done
shopt -u extglob # disable extended globbing, if necessary

, .JPG, , $i *.JPG ( ), , nullglob.

for file in *.JPG; do
    [ -e "${file}" ] || continue
    do_something_with "${file}"
done

shopt -s nullglob
for file *.JPG; do
    do_something_with "${file}"
done
shopt -u nullglob # if necessary

, , nullglob:

$ for f in *.doesnotexist; do echo "$f"; done
*.doesnotexist