Ah effectivement en mettant Sudo avant votre commande, le ciel s'éclaircit dirait on :
Setting up logger: /volume1/@appstore/Minecraft/forge.jar.log
java.net.preferIPv4Stack=true
Installing server to current directory
MESSAGE: Data kindly mirrored by Forge at
http://MinecraftForge.net/
MESSAGE: Considering minecraft server jar
MESSAGE: Downloading minecraft server version 1.12.2
ETag: 71728ed3fbd0acd1394bf3ade2649a5c
MD5: 71728ed3fbd0acd1394bf3ade2649a5c
MESSAGE: Considering library net.minecraftforge:forge:1.12.2-14.23.5.2768: Not Downloading {Wrong Side}
MESSAGE: Considering library net.minecraft:launchwrapper:1.12
MESSAGE: Downloading library net.minecraft:launchwrapper:1.12
MESSAGE: Trying unpacked library net.minecraft:launchwrapper:1.12
MESSAGE: Considering library org.ow2.asm:asm-all:5.2
MESSAGE: Downloading library org.ow2.asm:asm-all:5.2
MESSAGE: Trying unpacked library org.ow2.asm:asm-all:5.2
MESSAGE: Considering library org.jline:jline:3.5.1
MESSAGE: Downloading library org.jline:jline:3.5.1
MESSAGE: Trying unpacked library org.jline:jline:3.5.1
MESSAGE: Considering library net.java.dev.jna:jna:4.4.0
MESSAGE: Downloading library net.java.dev.jna:jna:4.4.0
MESSAGE: Trying unpacked library net.java.dev.jna:jna:4.4.0
MESSAGE: Considering library com.typesafe.akka:akka-actor_2.11:2.3.3
MESSAGE: Downloading library com.typesafe.akka:akka-actor_2.11:2.3.3
MESSAGE: Trying unpacked library com.typesafe.akka:akka-actor_2.11:2.3.3
MESSAGE: Considering library com.typesafe:config:1.2.1
MESSAGE: Downloading library com.typesafe:config:1.2.1
MESSAGE: Trying unpacked library com.typesafe:config:1.2.1
MESSAGE: Considering library org.scala-lang:scala-actors-migration_2.11:1.1.0
MESSAGE: Downloading library org.scala-lang:scala-actors-migration_2.11:1.1.0
MESSAGE: Trying unpacked library org.scala-lang:scala-actors-migration_2.11:1.1.0
MESSAGE: Considering library org.scala-lang:scala-compiler:2.11.1
MESSAGE: Downloading library org.scala-lang:scala-compiler:2.11.1
MESSAGE: Trying unpacked library org.scala-lang:scala-compiler:2.11.1
MESSAGE: Considering library org.scala-lang.plugins:scala-continuations-library_2.11:1.0.2
MESSAGE: Downloading library org.scala-lang.plugins:scala-continuations-library_2.11:1.0.2
MESSAGE: Trying unpacked library org.scala-lang.plugins:scala-continuations-library_2.11:1.0.2
MESSAGE: Considering library org.scala-lang.plugins:scala-continuations-plugin_2.11.1:1.0.2
MESSAGE: Downloading library org.scala-lang.plugins:scala-continuations-plugin_2.11.1:1.0.2
MESSAGE: Trying unpacked library org.scala-lang.plugins:scala-continuations-plugin_2.11.1:1.0.2
MESSAGE: Considering library org.scala-lang:scala-library:2.11.1
MESSAGE: Downloading library org.scala-lang:scala-library:2.11.1
MESSAGE: Trying unpacked library org.scala-lang:scala-library:2.11.1
MESSAGE: Considering library org.scala-lang:scala-parser-combinators_2.11:1.0.1
MESSAGE: Downloading library org.scala-lang:scala-parser-combinators_2.11:1.0.1
MESSAGE: Trying unpacked library org.scala-lang:scala-parser-combinators_2.11:1.0.1
MESSAGE: Considering library org.scala-lang:scala-reflect:2.11.1
MESSAGE: Downloading library org.scala-lang:scala-reflect:2.11.1
MESSAGE: Trying unpacked library org.scala-lang:scala-reflect:2.11.1
MESSAGE: Considering library org.scala-lang:scala-swing_2.11:1.0.1
MESSAGE: Downloading library org.scala-lang:scala-swing_2.11:1.0.1
MESSAGE: Trying unpacked library org.scala-lang:scala-swing_2.11:1.0.1
MESSAGE: Considering library org.scala-lang:scala-xml_2.11:1.0.2
MESSAGE: Downloading library org.scala-lang:scala-xml_2.11:1.0.2
MESSAGE: Trying unpacked library org.scala-lang:scala-xml_2.11:1.0.2
MESSAGE: Considering library lzma:lzma:0.0.1
MESSAGE: Downloading library lzma:lzma:0.0.1
MESSAGE: Trying unpacked library lzma:lzma:0.0.1
MESSAGE: Considering library net.sf.jopt-simple:jopt-simple:5.0.3
MESSAGE: Downloading library net.sf.jopt-simple:jopt-simple:5.0.3
MESSAGE: Trying unpacked library net.sf.jopt-simple:jopt-simple:5.0.3
MESSAGE: Considering library java3d:vecmath:1.5.2
MESSAGE: Downloading library java3d:vecmath:1.5.2
MESSAGE: Trying unpacked library java3d:vecmath:1.5.2
MESSAGE: Considering library net.sf.trove4j:trove4j:3.0.3
MESSAGE: Downloading library net.sf.trove4j:trove4j:3.0.3
MESSAGE: Trying unpacked library net.sf.trove4j:trove4j:3.0.3
MESSAGE: Considering library org.apache.maven:maven-artifact:3.5.3
MESSAGE: Downloading library org.apache.maven:maven-artifact:3.5.3
MESSAGE: Trying unpacked library org.apache.maven:maven-artifact:3.5.3
Extracting: /forge-1.12.2-14.23.5.2768-universal.jar
To: /volume1/@appstore/Minecraft/./forge-1.12.2-14.23.5.2768-universal.jar
The server installed successfully, you should now be able to run the file forge-1.12.2-14.23.5.2768-universal.jar
You can delete this installer file now if you wish
Cela parait mieux ! Dans mon dossier Minecraft j'ai 4 fichiers Jar maintenant. Je supprime les 2 premiers (forge.jar et Minecraft.jar ) ?