WORKDIR Instruction

WORKDIR sets the working directory inside a Docker image.

It is similar to using cd in a terminal, but it is written as a Dockerfile instruction. After Docker reaches a WORKDIR line, the following instructions run from that directory.

Why WORKDIR is useful

Without WORKDIR, you may need to write long paths again and again:

COPY app.jar /app/app.jar
CMD ["java", "-jar", "/app/app.jar"]

With WORKDIR, the Dockerfile becomes cleaner:

WORKDIR /app
COPY app.jar app.jar
CMD ["java", "-jar", "app.jar"]

Now Docker understands that app.jar is inside /app.

Basic syntax

The syntax is simple:

WORKDIR /app

If the directory does not exist, Docker creates it.

That means you usually do not need to run:

RUN mkdir /app

You can directly use WORKDIR /app.

Example with a Java application

A simple Dockerfile for a Java application may look like this:

FROM eclipse-temurin:17-jre
WORKDIR /app
COPY target/myapp.jar app.jar
EXPOSE 8080
CMD ["java", "-jar", "app.jar"]

Here is what happens:

WORKDIR affects later instructions

After this line:

WORKDIR /app

These instructions use /app as the current directory:

COPY . .
RUN ls
CMD ["node", "server.js"]

So COPY . . copies files into /app, RUN ls lists files inside /app, and CMD starts from /app.

Multiple WORKDIR instructions

You can use WORKDIR more than once:

WORKDIR /app
WORKDIR logs

The second line is relative to the first, so the final working directory becomes:

/app/logs

For beginner Dockerfiles, prefer one clear absolute WORKDIR, such as /app.

Good practice

Use WORKDIR in almost every application Dockerfile.

It makes paths easier to read and prevents confusion about where commands are running.

Written By: Shiva Srivastava