How to check if a directory exists in Linux bash shell?

To check if a directory exists in a bash shell script, use the following:

DIRECTORY="/some/path/dir"

if [ -d "$DIRECTORY" ]; then
  # perform some action if $DIRECTORY exists.
fi

DIRECTORY="/some/path/dir"

if [ -d "$DIRECTORY" ]; then

# perform some action if $DIRECTORY exists.

To check if a directory does not exists in a bash shell script, use the following:

if [ ! -d "$DIRECTORY" ]; then
  # perform some action if $DIRECTORY does not exists.
fi

if [ ! -d "$DIRECTORY" ]; then

# perform some action if $DIRECTORY does not exists.