## Créer et utiliser des variables d'environnement { #create-and-use-env-vars }

Vous pouvez créer et utiliser des variables d'environnement dans le **shell (terminal)**, sans avoir besoin de Python :

//// tab | Linux, macOS, Windows Bash

<div class="termy">

```console
// Vous pouvez créer une variable d'environnement MY_NAME avec
$ export MY_NAME="Wade Wilson"

	}

	references := make([]interface{}, 0, len(constraint.References))
	for _, field := range constraint.References {
		references = append(references, clause.Column{Name: field.DBName})
	}
	vars = append(vars, clause.Table{Name: constraint.Name}, foreignKeys, clause.Table{Name: constraint.ReferenceSchema.Table}, references)
	return
}

func (rel *Relationship) ParseConstraint() *Constraint {

		if !db.DryRun && db.Error == nil {
			ok, mode := hasReturning(db, supportReturning)
			if !ok {
				result, err := db.Statement.ConnPool.ExecContext(db.Statement.Context, db.Statement.SQL.String(), db.Statement.Vars...)

				if db.AddError(err) == nil {
					db.RowsAffected, _ = result.RowsAffected()

					if db.Statement.Result != nil {
						db.Statement.Result.Result = result

/// tip | 팁

만약 "환경 변수"가 무엇이고, 어떻게 사용하는지 알고 계시다면, 이 챕터를 스킵하셔도 좋습니다.

///

환경 변수(또는 "**env var**"라고도 합니다)는 파이썬 코드의 **바깥**인, **운영 체제**에 존재하는 변수이며, 파이썬 코드(또는 다른 프로그램에서도)에서 읽을 수 있습니다.

환경 변수는 애플리케이션 **설정**을 처리하거나, 파이썬의 **설치** 과정의 일부로 유용할 수 있습니다.

## 환경 변수를 만들고 사용하기 { #create-and-use-env-vars }

파이썬 없이도, **셸 (터미널)** 에서 환경 변수를 **생성** 하고 사용할 수 있습니다.

//// tab | Linux, macOS, Windows Bash

<div class="termy">

          println("Server: ${response.header("Server")}")
          println("Date: ${response.header("Date")}")
          println("Vary: ${response.headers("Vary")}")
        }
      }
    ```

=== ":material-language-java: Java"
    ```java
      private final OkHttpClient client = new OkHttpClient();

      public void run() throws Exception {

# ----------------------------------------------------------------------------
# Maven Start Up Batch script
#
# Required ENV vars:
# ------------------
#   JAVA_HOME - location of a JDK home dir
#
# Optional ENV vars
# -----------------
#   M2_HOME - location of maven2's installed home dir
#   MAVEN_OPTS - parameters passed to the Java VM when running Maven

	listType := r.Form.Get("listType")
	if listType != "sts-only" && listType != "svcacc-only" && listType != "" {
		// default to both
		listType = ""
	}

	var serviceAccounts []auth.Credentials
	var stsKeys []auth.Credentials

	if listType == "" || listType == "sts-only" {
		stsKeys, err = globalIAMSys.ListSTSAccounts(ctx, targetAccount)
		if err != nil {

  private val atomicRequestCount = AtomicInteger()

  private var serverSocketFactory_: ServerSocketFactory? = null
  private var serverSocket: ServerSocket? = null

  /** Non-null after [start]. */
  private var socketAddress_: InetSocketAddress? = null

  private var sslSocketFactory: SSLSocketFactory? = null
  private var clientAuth = CLIENT_AUTH_NONE

  private var closed: Boolean = false

  /**

Eine Umgebungsvariable (auch bekannt als „**env var**“) ist eine Variable, die **außerhalb** des Python-Codes im **Betriebssystem** lebt und von Ihrem Python-Code (oder auch von anderen Programmen) gelesen werden kann.

Umgebungsvariablen können nützlich sein, um **Einstellungen** der Anwendung zu handhaben, als Teil der **Installation** von Python usw.

## Umgebungsvariablen erstellen und verwenden { #create-and-use-env-vars }

	readerNoEOF := newTestReaderNoEOF(content)
	err := obj.MakeBucket(context.Background(), "bucket", MakeBucketOptions{})
	if err != nil {
		t.Fatalf("%s: <ERROR> %s", instanceType, err)
	}

	var bytesBuffer1 bytes.Buffer
	var opts ObjectOptions
	_, err = obj.PutObject(context.Background(), "bucket", "object", mustGetPutObjReader(t, readerEOF, length, "", ""), opts)
	if err != nil {
		t.Fatalf("%s: <ERROR> %s", instanceType, err)
	}