Script was run through https://www.shellcheck.net/
Some parts were not quoted or could have unwanted side effects like "rm -r /".
Remaining suggestions can be ignored IMO:
Line 106:
declare -rg date=$(date +"%Y%m%d-%H%M%S")
^-- SC2155: Declare and assign separately to avoid masking return values.
Line 123:
for dir in $(ls -t1 "$BACKUP_PATH" | tail -n +"$NUMBACKUPS"); do
^-- SC2012: Use find instead of ls to better handle non-alphanumeric filenames.
Line 137:
if [[ $? -ne 0 ]]; then
^-- SC2181: Check exit code directly with e.g. 'if mycmd;', not indirectly with $?.
Line 153:
dbs=$(ls ./*.sql | cut -d "." -f 1 | cut -d "-" -f 1 | sort | uniq)
^-- SC2012: Use find instead of ls to better handle non-alphanumeric filenames.
Line 188:
[[ $? -ne 0 ]] \
^-- SC2181: Check exit code directly with e.g. 'if mycmd;', not indirectly with $?.