Ubuntu Manpage: podman-exec - Execute a command in a running container

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NAME

       podman-exec - Execute a command in a running container

SYNOPSIS

       podman exec [options] container command [arg ...]

       podman container exec [options] container command [arg ...]

DESCRIPTION

       podman exec executes a command in a running container.

OPTIONS

--detach, -d
Start the exec session, but do not attach to it. The command runs in the background, and the exec session
is automatically removed when it completes. The podman exec command prints the ID of the exec session and
exits immediately after it starts.

--detach-keys=sequence
Specify the key sequence for detaching a container. Format is a single character [a-Z] or one or more
ctrl-<value> characters where <value> is one of: a-z, @, ^, [, , or _. Specifying "" disables this
feature. The default is ctrl-p,ctrl-q.

This option can also be set in containers.conf(5) file.

--env, -e=env
Set environment variables.

This option allows arbitrary environment variables that are available for the process to be launched
inside of the container. If an environment variable is specified without a value, Podman checks the host
environment for a value and set the variable only if it is set on the host. As a special case, if an
environment variable ending in * is specified without a value, Podman searches the host environment for
variables starting with the prefix and adds those variables to the container.

--env-file=file
Read in a line-delimited file of environment variables.

--interactive, -i
When set to true, make stdin available to the contained process. If false, the stdin of the contained
process is empty and immediately closed.

If attached, stdin is piped to the contained process. If detached, reading stdin will block until later
attached.

Caveat: Podman will consume input from stdin as soon as it becomes available, even if the contained
process doesn't request it.

--latest, -l
Instead of providing the container name or ID, use the last created container. Note: the last started
container can be from other users of Podman on the host machine. (This option is not available with the
remote Podman client, including Mac and Windows (excluding WSL2) machines)

--preserve-fd=FD1[,FD2,...]
Pass down to the process the additional file descriptors specified in the comma separated list. It can
be specified multiple times. This option is only supported with the crun OCI runtime. It might be a
security risk to use this option with other OCI runtimes.

(This option is not available with the remote Podman client, including Mac and Windows (excluding WSL2)
machines)

--preserve-fds=N
Pass down to the process N additional file descriptors (in addition to 0, 1, 2). The total FDs are 3+N.
(This option is not available with the remote Podman client, including Mac and Windows (excluding WSL2)
machines)

--privileged
Give extended privileges to this container. The default is false.

By default, Podman containers are unprivileged (=false) and cannot, for example, modify parts of the
operating system. This is because by default a container is only allowed limited access to devices. A
"privileged" container is given the same access to devices as the user launching the container, with the
exception of virtual consoles (/dev/tty\d+) when running in systemd mode (--systemd=always).

A privileged container turns off the security features that isolate the container from the host. Dropped
Capabilities, limited devices, read-only mount points, Apparmor/SELinux separation, and Seccomp filters
are all disabled. Due to the disabled security features, the privileged field should almost never be set
as containers can easily break out of confinement.

Containers running in a user namespace (e.g., rootless containers) cannot have more privileges than the
user that launched them.

--tty, -t
Allocate a pseudo-TTY. The default is false.

When set to true, Podman allocates a pseudo-tty and attach to the standard input of the container. This
can be used, for example, to run a throwaway interactive shell.

NOTE: The --tty flag prevents redirection of standard output. It combines STDOUT and STDERR, it can
insert control characters, and it can hang pipes. This option is only used when run interactively in a
terminal. When feeding input to Podman, use -i only, not -it.

--user, -u=user[:group]
Sets the username or UID used and, optionally, the groupname or GID for the specified command. Both user
and group may be symbolic or numeric.

Without this argument, the command runs as the user specified in the container image. Unless overridden
by a USER command in the Containerfile or by a value passed to this option, this user generally defaults
to root.

When a user namespace is not in use, the UID and GID used within the container and on the host match.
When user namespaces are in use, however, the UID and GID in the container may correspond to another UID
and GID on the host. In rootless containers, for example, a user namespace is always used, and root in
the container by default corresponds to the UID and GID of the user invoking Podman.

--workdir, -w=dir
Working directory inside the container.

The default working directory for running binaries within a container is the root directory (/). The
image developer can set a different default with the WORKDIR instruction. The operator can override the
working directory by using the -w option.

Exit Status

       The exit code from podman exec gives information about why the command within the container failed to run
       or why it exited.  When podman exec exits with  a  non-zero  code,  the  exit  codes  follow  the  chroot
       standard, see below:

       125 The error is with Podman itself

       $ podman exec --foo ctrID /bin/sh; echo $?
       Error: unknown flag: --foo
       125

       126 The contained command cannot be invoked

       $ podman exec ctrID /etc; echo $?
       Error: container_linux.go:346: starting container process caused "exec: \"/etc\": permission denied": OCI runtime error
       126

       127 The contained command cannot be found

       $ podman exec ctrID foo; echo $?
       Error: container_linux.go:346: starting container process caused "exec: \"foo\": executable file not found in $PATH": OCI runtime error
       127

       Exit code The contained command exit code

       $ podman exec ctrID /bin/sh -c 'exit 3'; echo $?
       3

EXAMPLES

       Execute command in selected container with a stdin and a tty allocated:

       $ podman exec -it ctrID ls

       Execute  command  with  the  overridden  working  directory  in selected container with a stdin and a tty
       allocated:

       $ podman exec -it -w /tmp myCtr pwd

       Execute command as the specified user in selected container:

       $ podman exec --user root ctrID ls

HISTORY

       December 2017, Originally compiled by Brent Baudebbaude@redhat.com ⟨mailto:bbaude@redhat.com⟩

                                                                                                  podman-exec(1)