The `podman volume export` command should refuse to write to STDOUT if it is a TTY

[mheon]

Issue Description

During a quick demo today, I noticed that podman volume export testVol with no redirection after will quite happily print the raw contents of tar to STDOUT. This could cause issues with the terminal if things like control characters are printed, and honestly doesn't seem useful at all; outputting to STDOUT only really makes sense if it's being piped into another command or redirected into a file.

Steps to reproduce the issue

Steps to reproduce the issue

1. podman volume create testVol
2. podman run -v testVol:/data --rm alpine sh -c "echo hello > /data/myfile"
3. podman volume export testVol

Describe the results you received

$ podman volume export testvol
myfile0000644000000000000000000000000615026530174010453 0ustar0000000000000000hello

Describe the results you expected

An error message refusing to export when STDOUT is a terminal.

podman info output

host:
  arch: amd64
  buildahVersion: 1.40.0
  cgroupControllers:
  - cpu
  - io
  - memory
  - pids
  cgroupManager: systemd
  cgroupVersion: v2
  conmon:
    package: conmon-2.1.13-1.fc41.x86_64
    path: /usr/bin/conmon
    version: 'conmon version 2.1.13, commit: '
  cpuUtilization:
    idlePercent: 90.39
    systemPercent: 1.68
    userPercent: 7.92
  cpus: 8
  databaseBackend: sqlite
  distribution:
    distribution: fedora
    variant: workstation
    version: "41"
  eventLogger: journald
  freeLocks: 2046
  hostname: IronDuke
  idMappings:
    gidmap:
    - container_id: 0
      host_id: 1000
      size: 1
    - container_id: 1
      host_id: 100000
      size: 65536
    uidmap:
    - container_id: 0
      host_id: 1000
      size: 1
    - container_id: 1
      host_id: 100000
      size: 65536
  kernel: 6.13.8-200.fc41.x86_64
  linkmode: dynamic
  logDriver: journald
  memFree: 3382812672
  memTotal: 33331769344
  networkBackend: netavark
  networkBackendInfo:
    backend: netavark
    dns:
      package: aardvark-dns-1.15.0-1.fc41.x86_64
      path: /usr/libexec/podman/aardvark-dns
      version: aardvark-dns 1.15.0
    package: netavark-1.15.0-1.fc41.x86_64
    path: /usr/libexec/podman/netavark
    version: netavark 1.15.0
  ociRuntime:
    name: crun
    package: crun-1.21-1.fc41.x86_64
    path: /usr/bin/crun
    version: |-
      crun version 1.21
      commit: 10269840aa07fb7e6b7e1acff6198692d8ff5c88
      rundir: /run/user/1000/crun
      spec: 1.0.0
      +SYSTEMD +SELINUX +APPARMOR +CAP +SECCOMP +EBPF +CRIU +LIBKRUN +WASM:wasmedge +YAJL
  os: linux
  pasta:
    executable: /usr/bin/pasta
    package: passt-0^20250512.g8ec1341-1.fc41.x86_64
    version: ""
  remoteSocket:
    exists: true
    path: /run/user/1000/podman/podman.sock
  rootlessNetworkCmd: pasta
  security:
    apparmorEnabled: false
    capabilities: CAP_CHOWN,CAP_DAC_OVERRIDE,CAP_FOWNER,CAP_FSETID,CAP_KILL,CAP_NET_BIND_SERVICE,CAP_SETFCAP,CAP_SETGID,CAP_SETPCAP,CAP_SETUID,CAP_SYS_CHROOT
    rootless: true
    seccompEnabled: true
    seccompProfilePath: /usr/share/containers/seccomp.json
    selinuxEnabled: true
  serviceIsRemote: false
  slirp4netns:
    executable: /usr/bin/slirp4netns
    package: slirp4netns-1.3.1-1.fc41.x86_64
    version: |-
      slirp4netns version 1.3.1
      commit: e5e368c4f5db6ae75c2fce786e31eef9da6bf236
      libslirp: 4.8.0
      SLIRP_CONFIG_VERSION_MAX: 5
      libseccomp: 2.5.5
  swapFree: 2007359488
  swapTotal: 8589930496
  uptime: 2185h 2m 55.00s (Approximately 91.04 days)
  variant: ""
plugins:
  authorization: null
  log:
  - k8s-file
  - none
  - passthrough
  - journald
  network:
  - bridge
  - macvlan
  - ipvlan
  volume:
  - local
registries:
  search:
  - registry.fedoraproject.org
  - registry.access.redhat.com
  - docker.io
store:
  configFile: /home/mheon/.config/containers/storage.conf
  containerStore:
    number: 0
    paused: 0
    running: 0
    stopped: 0
  graphDriverName: overlay
  graphOptions: {}
  graphRoot: /home/mheon/.local/share/containers/storage
  graphRootAllocated: 510389125120
  graphRootUsed: 96832303104
  graphStatus:
    Backing Filesystem: btrfs
    Native Overlay Diff: "true"
    Supports d_type: "true"
    Supports shifting: "false"
    Supports volatile: "true"
    Using metacopy: "false"
  imageCopyTmpDir: /var/tmp
  imageStore:
    number: 9
  runRoot: /run/user/1000/containers
  transientStore: false
  volumePath: /home/mheon/.local/share/containers/storage/volumes
version:
  APIVersion: 5.5.0
  BuildOrigin: Fedora Project
  Built: 1747180800
  BuiltTime: Tue May 13 20:00:00 2025
  GitCommit: 0dbcb51477ee7ab8d3b47d30facf71fc38bb0c98
  GoVersion: go1.23.8
  Os: linux
  OsArch: linux/amd64
  Version: 5.5.0

Podman in a container

No

Privileged Or Rootless

None

Upstream Latest Release

Yes

Additional environment details

100% reproducible and should apply to every release of Podman with this command.

Additional information

No response

[Luap99]

Note while the code change itself should be easy it needs some more attention for a proper test. Tests by default won't have a tty since we already capture their output, however we already have some pty setup in test/system/450-interactive.bats so a test could be added there.

[ArthurWuTW]

/assign