How to check if Docker is installed in a Unix shell script? [duplicate]

Question

I need to check in a shell script if Docker is installed (Ubuntu server).

I came up with this, but the syntax is not correct.

if [[ which docker && docker --version ]]; then
  echo "Update docker"
  # command
else
  echo "Install docker"
  # command
fi

I also tried if [ which docker ] && [ docker --version ]; then

Christian Desserich · Accepted Answer · 2017-10-04 22:42:06Z

35

Using suggestions from the answer in rickdenhaan's comment:

if [ -x "$(command -v docker)" ]; then
    echo "Update docker"
    # command
else
    echo "Install docker"
    # command
fi

answered Oct 4, 2017 at 22:42

Christian Desserich

5923 silver badges11 bronze badges

Sign up to request clarification or add additional context in comments.

4 Comments

user3142695 Over a year ago

What does -x do? For me if command -v docker; then is working.

Christian Desserich Over a year ago

It tests if a file exists and is executable. The command command returns the docker command's location, then the -x flag tests that it there and able to execute.

Christian Desserich Over a year ago

The brackets are an alias the the test command. Run man test to see all the flags and their descriptions.

Cognitive Hazard Over a year ago

Is there any reason why command -v docker would be preferred over which docker ?

ipeacocks · Accepted Answer · 2017-10-04 22:40:49Z

8

This one is working for me:

if [[ $(which docker) && $(docker --version) ]]; then
    echo "Update docker"
    # command
  else
    echo "Install docker"
    # command
fi

answered Oct 4, 2017 at 22:40

ipeacocks

2,3173 gold badges35 silver badges49 bronze badges

Collectives™ on Stack Overflow

How to check if Docker is installed in a Unix shell script? [duplicate]

2 Answers 2

4 Comments

Comments

Linked

Hot Network Questions

Collectives™ on Stack Overflow

2 Answers 2

4 Comments

Comments

Linked

Related