* The **file** that can be **executed** by the operating system, for example: `python`, `python.exe` or `uvicorn`.
* A particular program while it is **running** on the operating system, using the CPU, and storing things on memory. This is also called a **process**.

### What is a Process

The word **process** is normally used in a more specific way, only referring to the thing that is running in the operating system (like in the last point above):

An <a href="https://en.wikipedia.org/wiki/Environment_variable" class="external-link" target="_blank">environment variable</a> (also known as "env var") is a variable that lives outside of the Python code, in the operating system, and could be read by your Python code (or by other programs as well).

You can create and use environment variables in the shell, without needing Python:

=== "Linux, macOS, Windows Bash"

    <div class="termy">

Your code needs to run on [all versions of Java that Gradle supports](platforms/documentation/docs/src/docs/userguide/releases/compatibility.adoc) and across all supported operating systems (macOS, Windows, Linux). The [Gradle CI system](http://builds.gradle.org/) will verify this, but here are some pointers that will avoid surprises:

Linux containers run using the same Linux kernel of the host (machine, virtual machine, cloud server, etc). This just means that they are very lightweight (compared to full virtual machines emulating an entire operating system).

This way, containers consume **little resources**, an amount comparable to running the processes directly (a virtual machine would consume much more).

	MTime                time.Time // Is only set in POST/PUT operations
	Expires              time.Time // Is only used in POST/PUT operations

	DeleteMarker            bool // Is only set in DELETE operations for delete marker replication
	CheckDMReplicationReady bool // Is delete marker ready to be replicated - set only during HEAD
	Tagging                 bool // Is only in GET/HEAD operations to return tagging metadata along with regular metadata and body.

    It is the "**path operation decorator**".

You can also use the other operations:

* `@app.post()`
* `@app.put()`
* `@app.delete()`

And the more exotic ones:

* `@app.options()`
* `@app.head()`
* `@app.patch()`
* `@app.trace()`

!!! tip
    You are free to use each operation (HTTP method) as you wish.

	if err != nil {
		return err
	}
	status, err := reconciler.Reconcile()
	if err != nil {
		return fmt.Errorf("errors occurred during operation: %v", err)
	}
	if status.Status != v1alpha1.InstallStatus_HEALTHY {
		return fmt.Errorf("errors occurred during operation")
	}

	// Previously we may install IOP file from the old version of istioctl. Now since we won't install IOP file

 * detailed at {@link ImmutableCollection}.
 *
 * <p><b>Grouped iteration.</b> In all current implementations, duplicate elements always appear
 * consecutively when iterating. Elements iterate in order by the <i>first</i> appearance of that
 * element when the multiset was created.
 *
 * <p>See the Guava User Guide article on <a href=

   * @deprecated Unsupported operation.
   */
  @Deprecated
  @Override
  @DoNotCall("Always throws UnsupportedOperationException")
  public void remove(Range<C> range) {
    throw new UnsupportedOperationException();
  }

  /**
   * Guaranteed to throw an exception and leave the {@code RangeSet} unmodified.
   *
   * @throws UnsupportedOperationException always
   * @deprecated Unsupported operation.
   */

   * in {@code occurrencesToRemove}. However, this operation <i>is</i> equivalent to, albeit
   * sometimes more efficient than, the following:
   *
   * <pre>{@code
   * for (E e : occurrencesToRemove) {
   *   multisetToModify.remove(e);
   * }
   * }</pre>
   *
   * @return {@code true} if {@code multisetToModify} was changed as a result of this operation