command – Execute commands on targets

From Get docs
Ansible/docs/2.8/modules/command module


command – Execute commands on targets

Synopsis

  • The 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 $HOME and operations like "<", ">", "|", ";" and "&" will not work. Use the shell module if you need these features.
  • To create command tasks that are easier to read, pass parameters using the args task keyword.
  • For Windows targets, use the win_command module instead.

Parameters

Parameter Choices/Defaults Comments

argv

list

added in 2.6

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 or the list form can be provided, not both. One or the other must be provided.

chdir

path

Change into this directory before running the command.

creates

path

A filename or (since 2.0) glob pattern. If it already exists, this step won't be run.

free_form

- / required

The command module takes a free form command to run.

There is no actual parameter named 'free form'.

See the examples on how to use this module.

removes

path

A filename or (since 2.0) glob pattern. If it already exists, this step will be run.

stdin

-

added in 2.4

Set the stdin of the command directly to the specified value.

stdin_add_newline

boolean

added in 2.8

  • no
  • yes

If set to yes, append a newline to stdin data.

strip_empty_ends

boolean

added in 2.8

  • no
  • yes

Strip empty lines from the end of stdout/stderr in result.

warn

boolean

  • no
  • yes

Enable or disable task warnings.



Notes

Note

  • If you want to run a command through the shell (say you are using <, >, |, etc), you actually want the 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 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 shell module instead.
  • For Windows targets, use the win_command module instead.
  • For rebooting systems, use the reboot or win_reboot module.


See Also

See also

raw – Executes a low-down and dirty command
The official documentation on the raw module.
script – Runs a local script on a remote node after transferring it
The official documentation on the script module.
shell – Execute shell commands on targets
The official documentation on the shell module.
win_command – Executes a command on a remote Windows node
The official documentation on the win_command module.


Examples

- name: return motd to registered var
  command: cat /etc/motd
  register: mymotd

- name: Run command if /path/to/database does not exist (without 'args').
  command: /usr/bin/make_database.sh db_user db_name creates=/path/to/database

# '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').
  command: /usr/bin/make_database.sh db_user db_name
  args:
    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.
  command: /usr/bin/make_database.sh db_user db_name
  become: yes
  become_user: db_owner
  args:
    chdir: somedir/
    creates: /path/to/database

# 'argv' is a parameter, indented one level from the module
- name: Use 'argv' to send a command as a list - leave 'command' empty
  command:
    argv:
      - /usr/bin/make_database.sh
      - Username with whitespace
      - dbname with whitespace

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

Return Values

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

Key Returned Description

cmd

list

always

the cmd that was run on the remote machine


Sample:

['echo', 'hello']

delta

string

always

cmd end time - cmd start time


Sample:

0.001529

end

string

always

cmd end time


Sample:

2017-09-29 22:03:48.084657

start

string

always

cmd start time


Sample:

2017-09-29 22:03:48.083128




Status

Red Hat Support

More information about Red Hat’s support of this module is available from this Red Hat Knowledge Base article.

Authors

  • Ansible Core Team
  • Michael DeHaan

Hint

If you notice any issues in this documentation you can edit this document to improve it.


© 2012–2018 Michael DeHaan
© 2018–2019 Red Hat, Inc.
Licensed under the GNU General Public License version 3.
https://docs.ansible.com/ansible/2.8/modules/command_module.html