docs: Correct run exit code 126 description

[noahsilas]

The command to run inside the container is /etc. The semicolon is a statement terminator, which ends the command docker run busybox /etc, while echo $? prints the exit code of that full docker command.

Having this mistake could confuse someone who thinks that /etc; echo $? is all run inside the container, which wouldn't help the reader understand the exit code of the docker run command itself.

[codecov-commenter]

Codecov Report

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Additional details and impacted files

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  Misses      10824    10824           
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[thaJeztah]

Thank you!

We should probably consider (but not for this PR) writing them as separate steps, i.e., run a container, then check the exit-code

That said, it looks like with integration with runc and later containerd, the error-messages that's now returned for invalid commands have become rather verbose; each layer adding its own decoration, which means that there's now many details that may not be relevant to the user;

$ docker run --rm busybox /etc
docker: Error response from daemon: failed to create task for container: failed to create shim task: OCI runtime create failed: runc create failed: unable to start container process: exec: "/etc": permission denied: unknown.

$ echo $?
126

$ docker run --rm busybox nosuchcommand
docker: Error response from daemon: failed to create task for container: failed to create shim task: OCI runtime create failed: runc create failed: unable to start container process: exec: "nosuchcommand": executable file not found in $PATH: unknown.

$ echo $?
127

$ docker run --rm busybox /nosuchcommand
docker: Error response from daemon: failed to create task for container: failed to create shim task: OCI runtime create failed: runc create failed: unable to start container process: exec: "/nosuchcommand": stat /nosuchcommand: no such file or directory: unknown.

$ echo $?
127

[thaJeztah]

LGTM

let me bring this one in; I'll open a tracking ticket for the other bits

[noahsilas]

Thanks for the quick feedback and merge @thaJeztah! I appreciate the work you are doing here 😁