Heads up! To view this whole video, sign in with your Courses account or enroll in your free 7-day trial. Sign In Enroll
Preview
Start a free Courses trial
to watch this video
The RUN instruction will execute a command of your choosing while building the image. The command will be run exactly as if you had typed it in a shell on the guest OS. You can use these commands to permanently update the contents of the image. RUN is useful for installing dependencies or running a script in the container at build time.
The run instruction will execute
the command of your choosing while
0:00
building the image.
0:04
The command will be run exactly as if you
had typed in a shell on the guest OS.
0:05
You can use these commands to permanently
update the contents of the image.
0:10
Run is useful for
installing dependencies or
0:15
running a script in
the container at build time.
0:17
This pair of commands here both run
the ubuntu apps get package manager.
0:20
The first updates the list
of available packages and
0:24
the second uses that updated
list to install python3.
0:28
The form of one instruction shown here is
called the shell form which will execute
0:31
the given command using a shell like bash.
0:35
You should use this form if there
are environment variables or
0:39
file name wild cards whose values you
want substituted into the command.
0:42
The second form of RUN
is called the exec form.
0:47
Let me convert this first
instruction to exec form.
0:50
We use JSON array syntax
with square brackets.
0:53
We'll surround each element
with quotation marks and
0:59
we'll separate the elements with commas.
1:01
The first element should be
the executable you want to run,
1:04
in this case that's apt-get.
1:07
All subsequent elements
are arguments to that executable.
1:10
The exec form just passes your parameters
directly to the given executable
1:14
without invoking a shell or
doing any substitution.
1:19
You should use the exec form if you want
to be very precise about the arguments you
1:22
pass to the executable.
1:26
So to finish converting this one, we'll
use update as our second argument and
1:28
-y as our third.
1:33
And this run instruction in exec form
is identical in meaning to this run
1:37
instruction in shell form.
1:41
You need to sign up for Treehouse in order to download course files.
Sign up