Bash has extended globbing (first test, then remove the echo):
shopt -s extglob
echo rm -rf !(A)
find -maxdepth 1 -type d -not -name A -not -name "." -exec rm -ir {} \;
Delete all sub-directories except one
Bash has extended globbing (first test, then remove the echo):
shopt -s extglob
echo rm -rf !(A)
find -maxdepth 1 -type d -not -name A -not -name "." -exec rm -ir {} \;