Shortcut to execute docker exec -it ID bash

dockerbash

#!/bin/bash

# Print out a list of docker containers.
i=0
firstrun=0
while read x
do
    if [ $firstrun == 0 ]
    then
        echo "$x"
    else
        echo "[$i] $x"
        i=$((i+1))
    fi
    firstrun=1
done << EOF
$(docker ps)
EOF

# Ask for container index
read container_index

# Get requested container id
i=0
container_id=""
for x in `docker ps -q`
do
        if [ $container_index == $i ]
        then
                container_id=$x
        fi
        i=$(($i+1))
done

# Run bash.
docker exec -it $container_id bash

If you change the last line to this, it would fall back to shell if bash is not available (some containers don't have bash)
docker exec -it $container_id sh -c '/bin/bash || /bin/sh'