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 $HOSTNAME 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 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 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 (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 won't be run.
free_form
-
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.
stdin
-
added in 2.4
Set the stdin of the command directly to the specified value.
stdin_add_newline
boolean
added in 2.8
    Choices:
  • no
  • yes ←
If set to yes, append a newline to stdin data.
strip_empty_ends
boolean
added in 2.8
    Choices:
  • no
  • yes ←
Strip empty lines from the end of stdout/stderr in result.
warn
boolean
    Choices:
  • 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

# free-form (string) arguments, all arguments on one line
- 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

# 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).
  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).
  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.
  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
  command:
    argv:
      - /usr/bin/make_database.sh
      - Username with whitespace
      - dbname with whitespace
    creates: /path/to/database

- 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 command executed by the task

Sample:
['echo', 'hello']
delta
string
always
The command execution delta time

Sample:
0:00:00.001529
end
string
always
The command execution end time

Sample:
2017-09-29 22:03:48.084657
msg
boolean
always
changed

Sample:
True
rc
integer
always
The command return code (0 means success)

start
string
always
The command execution start time

Sample:
2017-09-29 22:03:48.083128
stderr
string
always
The command standard error

Sample:
ls cannot access foo: No such file or directory
stderr_lines
list
always
The command standard error split in lines

Sample:
[{"u'ls cannot access foo": "No such file or directory'"}, "u'ls …'"]
stdout
string
always
The command standard output

Sample:
Clustering node [email protected] with [email protected]
stdout_lines
list
always
The command standard output split in lines

Sample:
["u'Clustering node [email protected] with [email protected] …'"]


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.