replace – Replace all instances of a particular string in a file using a back-referenced regular expression

Synopsis

  • This module will replace all instances of a pattern within a file.
  • It is up to the user to maintain idempotence by ensuring that the same pattern would never match any replacements made.

Parameters

Parameter Choices/Defaults Comments
after
string
added in 2.4
If specified, only content after this match will be replaced/removed.
Can be used in combination with before.
Uses Python regular expressions; see http://docs.python.org/2/library/re.html.
Uses DOTALL, which means the . special character can match newlines.
attributes
string
The attributes the resulting file or directory should have.
To get supported flags look at the man page for chattr on the target system.
This string should contain the attributes in the same order as the one displayed by lsattr.
The = operator is assumed as default, otherwise + or - operators need to be included in the string.

aliases: attr
backup
boolean
    Choices:
  • no ←
  • yes
Create a backup file including the timestamp information so you can get the original file back if you somehow clobbered it incorrectly.
before
string
added in 2.4
If specified, only content before this match will be replaced/removed.
Can be used in combination with after.
Uses Python regular expressions; see http://docs.python.org/2/library/re.html.
Uses DOTALL, which means the . special character can match newlines.
encoding
string
added in 2.4
 Default:
"utf-8"
The character encoding for reading and writing the file.
group
string
Name of the group that should own the file/directory, as would be fed to chown.
mode
string
The permissions the resulting file or directory should have.
For those used to /usr/bin/chmod remember that modes are actually octal numbers. You must either add a leading zero so that Ansible's YAML parser knows it is an octal number (like 0644 or 01777) or quote it (like '644' or '1777') so Ansible receives a string and can do its own conversion from string into number.
Giving Ansible a number without following one of these rules will end up with a decimal number which will have unexpected results.
As of Ansible 1.8, the mode may be specified as a symbolic mode (for example, u+rwx or u=rw,g=r,o=r).
As of Ansible 2.6, the mode may also be the special string preserve.
When set to preserve the file will be given the same permissions as the source file.
others
string
All arguments accepted by the file module also work here.
owner
string
Name of the user that should own the file/directory, as would be fed to chown.
path
path / required
The file to modify.
Before Ansible 2.3 this option was only usable as dest, destfile and name.

aliases: dest, destfile, name
regexp
string / required
The regular expression to look for in the contents of the file.
Uses Python regular expressions; see http://docs.python.org/2/library/re.html.
Uses MULTILINE mode, which means ^ and $ match the beginning and end of the file, as well as the beginning and end respectively of each line of the file.
Does not use DOTALL, which means the . special character matches any character except newlines. A common mistake is to assume that a negated character set like [^#] will also not match newlines.
In order to exclude newlines, they must be added to the set like [^#\n].
Note that, as of Ansible 2.0, short form tasks should have any escape sequences backslash-escaped in order to prevent them being parsed as string literal escapes. See the examples.
replace
string
The string to replace regexp matches.
May contain backreferences that will get expanded with the regexp capture groups if the regexp matches.
If not set, matches are removed entirely.
Backreferences can be used ambiguously like \1, or explicitly like \g<1>.
selevel
string
Default:
"s0"
The level part of the SELinux file context.
This is the MLS/MCS attribute, sometimes known as the range.
When set to _default, it will use the level portion of the policy if available.
serole
string
The role part of the SELinux file context.
When set to _default, it will use the role portion of the policy if available.
setype
string
The type part of the SELinux file context.
When set to _default, it will use the type portion of the policy if available.
seuser
string
The user part of the SELinux file context.
By default it uses the system policy, where applicable.
When set to _default, it will use the user portion of the policy if available.
unsafe_writes
boolean
    Choices:
  • no ←
  • yes
Influence when to use atomic operation to prevent data corruption or inconsistent reads from the target file.
By default this module uses atomic operations to prevent data corruption or inconsistent reads from the target files, but sometimes systems are configured or just broken in ways that prevent this. One example is docker mounted files, which cannot be updated atomically from inside the container and can only be written in an unsafe manner.
This option allows Ansible to fall back to unsafe methods of updating files when atomic operations fail (however, it doesn't force Ansible to perform unsafe writes).
IMPORTANT! Unsafe writes are subject to race conditions and can lead to data corruption.
validate
string
The validation command to run before copying into place.
The path to the file to validate is passed in via '%s' which must be present as in the examples below.
The command is passed securely so shell features like expansion and pipes will not work.

Notes

Note

  • As of Ansible 2.3, the dest option has been changed to path as default, but dest still works as well.
  • As of Ansible 2.7.10, the combined use of before and after works properly. If you were relying on the previous incorrect behavior, you may be need to adjust your tasks. See https://github.com/ansible/ansible/issues/31354 for details.
  • Option follow has been removed in Ansible 2.5, because this module modifies the contents of the file so follow=no doesn’t make sense.

Examples

- name: Before Ansible 2.3, option 'dest', 'destfile' or 'name' was used instead of 'path'
  replace:
    path: /etc/hosts
    regexp: '(\s+)old\.host\.name(\s+.*)?$'
    replace: '\1new.host.name\2'

- name: Replace after the expression till the end of the file (requires Ansible >= 2.4)
  replace:
    path: /etc/apache2/sites-available/default.conf
    after: 'NameVirtualHost [*]'
    regexp: '^(.+)$'
    replace: '# \1'

- name: Replace before the expression till the begin of the file (requires Ansible >= 2.4)
  replace:
    path: /etc/apache2/sites-available/default.conf
    before: '# live site config'
    regexp: '^(.+)$'
    replace: '# \1'

# Prior to Ansible 2.7.10, using before and after in combination did the opposite of what was intended.
# see https://github.com/ansible/ansible/issues/31354 for details.
- name: Replace between the expressions (requires Ansible >= 2.4)
  replace:
    path: /etc/hosts
    after: '<VirtualHost [*]>'
    before: '</VirtualHost>'
    regexp: '^(.+)$'
    replace: '# \1'

- name: Supports common file attributes
  replace:
    path: /home/jdoe/.ssh/known_hosts
    regexp: '^old\.host\.name[^\n]*\n'
    owner: jdoe
    group: jdoe
    mode: '0644'

- name: Supports a validate command
  replace:
    path: /etc/apache/ports
    regexp: '^(NameVirtualHost|Listen)\s+80\s*$'
    replace: '\1 127.0.0.1:8080'
    validate: '/usr/sbin/apache2ctl -f %s -t'

- name: Short form task (in ansible 2+) necessitates backslash-escaped sequences
  replace: path=/etc/hosts regexp='\\b(localhost)(\\d*)\\b' replace='\\1\\2.localdomain\\2 \\1\\2'

- name: Long form task does not
  replace:
    path: /etc/hosts
    regexp: '\b(localhost)(\d*)\b'
    replace: '\1\2.localdomain\2 \1\2'

- name: Explicitly specifying positional matched groups in replacement
  replace:
    path: /etc/ssh/sshd_config
    regexp: '^(ListenAddress[ ]+)[^\n]+$'
    replace: '\g<1>0.0.0.0'

- name: Explicitly specifying named matched groups
  replace:
    path: /etc/ssh/sshd_config
    regexp: '^(?P<dctv>ListenAddress[ ]+)(?P<host>[^\n]+)$'
    replace: '#\g<dctv>\g<host>\n\g<dctv>0.0.0.0'

Status

Authors

  • Evan Kaufman (@EvanK)

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