ansible.builtin.command module – Execute commands on targets

Note

This module is part of ansible-core and included in all Ansible installations. In most cases, you can use the short module name command even without specifying the collections keyword. However, we recommend you use the Fully Qualified Collection Name (FQCN) ansible.builtin.command for easy linking to the module documentation and to avoid conflicting with other collections that may have the same module name.

Synopsis

• The ansible.builtin.command module takes the command name followed by a list of space-delimited arguments.

• The given command will be executed on all selected nodes.

• The command(s) will not be processed through the shell, so variables like $HOSTNAME and operations like "*", "<", ">", "|", ";" and "&" will not work. Use the ansible.builtin.shell module if you need these features.

• To create command tasks that are easier to read than the ones using space-delimited arguments, pass parameters using the args task keyword or use cmd parameter.

• Either a free form command or cmd parameter is required, see the examples.

• For Windows targets, use the ansible.windows.win_command module instead.

Note

This module has a corresponding action plugin.

Parameters

Parameter	Comments
argv list / elements=string	Passes the command as a list rather than a string. Use argv to avoid quoting values that would otherwise be interpreted incorrectly (for example “user name”). Only the string (free form) or the list (argv) form can be provided, not both. One or the other must be provided.
chdir path	Change into this directory before running the command.
cmd string	The command to run.
creates path	A filename or (since 2.0) glob pattern. If a matching file already exists, this step will not be run. This is checked before removes is checked.
expand_argument_vars boolean added in ansible-core 2.16	Expands the arguments that are variables, for example $HOME will be expanded before being passed to the command to run. Set to false to disable expansion and treat the value as a literal argument. Choices: false true ← (default)
free_form string	The command module takes a free form string as a command to run. There is no actual parameter named ‘free form’.
removes path	A filename or (since 2.0) glob pattern. If a matching file exists, this step will be run. This is checked after creates is checked.
stdin string	Set the stdin of the command directly to the specified value.
stdin_add_newline boolean added in Ansible 2.8	If set to true, append a newline to stdin data. Choices: false true ← (default)
strip_empty_ends boolean added in Ansible 2.8	Strip empty lines from the end of stdout/stderr in result. Choices: false true ← (default)

Attributes

Attribute	Support	Description
check_mode	Support: partial while the command itself is arbitrary and cannot be subject to the check mode semantics it adds creates/removes options as a workaround	Can run in check_mode and return changed status prediction without modifying target, if not supported the action will be skipped.
diff_mode	Support: none	Will return details on what has changed (or possibly needs changing in check_mode), when in diff mode
platform	Platform: posix	Target OS/families that can be operated against
raw	Support: full	Indicates if an action takes a ‘raw’ or ‘free form’ string as an option and has it’s own special parsing of it

Notes

Note

• If you want to run a command through the shell (say you are using <, >, |, and so on), you actually want the ansible.builtin.shell module instead. Parsing shell metacharacters can lead to unexpected commands being executed if quoting is not done correctly so it is more secure to use the ansible.builtin.command module when possible.

• creates, removes, and chdir can be specified after the command. For instance, if you only want to run a command if a certain file does not exist, use this.

• Check mode is supported when passing creates or removes. If running in check mode and either of these are specified, the module will check for the existence of the file and report the correct changed status. If these are not supplied, the task will be skipped.

• The executable parameter is removed since version 2.4. If you have a need for this parameter, use the ansible.builtin.shell module instead.

• For Windows targets, use the ansible.windows.win_command module instead.

• For rebooting systems, use the ansible.builtin.reboot or ansible.windows.win_reboot module.

• If the command returns non UTF-8 data, it must be encoded to avoid issues. This may necessitate using ansible.builtin.shell so the output can be piped through base64.

See Also

See also

ansible.builtin.raw

Executes a low-down and dirty command.

ansible.builtin.script

Runs a local script on a remote node after transferring it.

ansible.builtin.shell

Execute shell commands on targets.

ansible.windows.win_command

Executes a command on a remote Windows node.

Examples

- name: Return motd to registered var
  ansible.builtin.command: cat /etc/motd
  register: mymotd

# free-form (string) arguments, all arguments on one line
- name: Run command if /path/to/database does not exist (without 'args')
  ansible.builtin.command: /usr/bin/make_database.sh db_user db_name creates=/path/to/database

# free-form (string) arguments, some arguments on separate lines with the 'args' keyword
# 'args' is a task keyword, passed at the same level as the module
- name: Run command if /path/to/database does not exist (with 'args' keyword)
  ansible.builtin.command: /usr/bin/make_database.sh db_user db_name
  args:
    creates: /path/to/database

# 'cmd' is module parameter
- name: Run command if /path/to/database does not exist (with 'cmd' parameter)
  ansible.builtin.command:
    cmd: /usr/bin/make_database.sh db_user db_name
    creates: /path/to/database

- name: Change the working directory to somedir/ and run the command as db_owner if /path/to/database does not exist
  ansible.builtin.command: /usr/bin/make_database.sh db_user db_name
  become: yes
  become_user: db_owner
  args:
    chdir: somedir/
    creates: /path/to/database

# argv (list) arguments, each argument on a separate line, 'args' keyword not necessary
# 'argv' is a parameter, indented one level from the module
- name: Use 'argv' to send a command as a list - leave 'command' empty
  ansible.builtin.command:
    argv:
      - /usr/bin/make_database.sh
      - Username with whitespace
      - dbname with whitespace
    creates: /path/to/database

- name: Run command using argv with mixed argument formats
  ansible.builtin.command:
    argv:
      - /path/to/binary
      - -v
      - --debug
      - --longopt
      - value for longopt
      - --other-longopt=value for other longopt
      - positional

- name: Safely use templated variable to run command. Always use the quote filter to avoid injection issues
  ansible.builtin.command: cat {{ myfile|quote }}
  register: myoutput

Return Values

Common return values are documented here, the following are the fields unique to this module:

Key	Description
cmd list / elements=string	The command executed by the task. Returned: always Sample: ["echo", "hello"]
delta string	The command execution delta time. Returned: always Sample: "0:00:00.001529"
end string	The command execution end time. Returned: always Sample: "2017-09-29 22:03:48.084657"
msg boolean	changed Returned: always Sample: true
rc integer	The command return code (0 means success). Returned: always Sample: 0
start string	The command execution start time. Returned: always Sample: "2017-09-29 22:03:48.083128"
stderr string	The command standard error. Returned: always Sample: "ls cannot access foo: No such file or directory"
stderr_lines list / elements=string	The command standard error split in lines. Returned: always Sample: [{"u'ls cannot access foo": "No such file or directory'"}, "u'ls \u2026'"]
stdout string	The command standard output. Returned: always Sample: "Clustering node rabbit@slave1 with rabbit@master \u2026"
stdout_lines list / elements=string	The command standard output split in lines. Returned: always Sample: ["u'Clustering node rabbit@slave1 with rabbit@master \u2026'"]

Authors

• Ansible Core Team

• Michael DeHaan

Collection links

• Issue Tracker
• Repository (Sources)
• Communication