I'm working on a bash scripts that will essentially shift the entire contents of a directory, where the filenames all start with a number (0001, 0002, etc). I'm iterating in reverse order through those files to shift the last one down first.
I have one function that iterates through the files and calls another function to actually shift them. When I call the second function, it short-circuits the for loop and exits. I can't figure out why.
validation_dir="scripts/validation"
content_directories=($validation_dir "tutorials")
function shift_contents() {
local start_index=$1
local positions=$2
local files=(${validation_dir}/*)
for ((i=${#files[@]}-1; i>=0; i--)); do
# Only gets called once
echo $i
local f="${files[$i]}"
local old_index=$(echo $f | tr -dc '0-9' | sed -e 's/^0*//')
if [ "$old_index" -lt "$start_index" ]
then
# Only start when we're at the start index
continue
fi
local new_index=$((old_index + positions))
# When this is called, it exits the loop
move_exercise $old_index $new_index
done
}
Here's the function that does the shifting:
function move_exercise() {
local start_index=$1
local end_index=$2
local start_prefix=$(echo_filename_prefix $start_index)
local end_prefix=$(echo_filename_prefix $end_index)
for i in ${content_directories[@]}; do
start_file_glob="${i}/${start_prefix}*"
for f in $start_file_glob; do
if [ -e $f ]
then
start_filename=$f
else
log_error "No content found with index ${start_index}"
exit 1
fi
break
done
end_file_glob="${i}/${end_prefix}*"
if [ -e $end_file_glob ]
then
log_error "Content was already found for end index ${end_index}: ${end_file_glob}"
exit 1
fi
# Generate the new file name
new_filename="${start_filename/$start_prefix/$end_prefix}"
# We get down here once
echo $start_filename $new_filename
done
return
}
It looks like the second function is causing the first to exit early, but I don't see how that could happen. See what's going on?
EDIT:
When I run with bash -x script.sh, it ends with the following output when it should have one more iteration:
+ echo path/to/second-to-last-file new-path
+ return
+ (( i-- ))
+ (( i>=0 ))
Does that imply that it's failing the for loop condition check? If so, how could move_exercise impact that? If I comment out that line, it works as expected.
If you want i to be local, you need to declare it as such:
shift_contents() {
local i
# ...etc...
}
move_exercise() {
local i
# ...etc...
}
Otherwise there's only one variable named i shared between both functions. When that variable contains a filename, its numeric value is 0 (unless that filename is also the name of a shell variable with a nonzero numeric value assigned) -- so when you decrement it after assigning a filename, it becomes negative.
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