图片 10

lineinfile实例讲解

By admin in 百科 on 2019年12月29日

lineinfile模块详解

最后一次修改于2017-05-24
10:34分,个人原创,转摘请加上原文链接

lineinfile模块类似linux工具中的sed工具,但是网上的文章一般都只有简单的实例,复杂点的例子都没有

下面是我根据实际操作总结出来的lineinfile模块的常见例子,分享给大家参考

目录

ansible-doc lineinfile官方文档(英文)–看不懂跳过直接看例子

1、需求:替换匹配的目标值… 

2、需求:在匹配值之前增加行… 

3、需求:在匹配值之后增加行… 

4、需求:匹配到就替换行,未匹配到就新增行… 

ansible-doc lineinfile

> LINEINFILE

 

  This module will search a file for a line, and ensure that it is present or absent. This is primarily useful when you want to change a single line in a file only. See the [replace] module if you want to change multiple, similar lines or chec [blockinfile] if you want to insert/update/remove a block of lines in a file. For other cases, see the [copy] or [template] modules.

 

Options (= is mandatory):

 

– backrefs

        Used with `state=present’. If set, line can contain backreferences (both positional and named) that will get populated

 if the `regexp’ matches. This flag changes the operation of the module slightly; `insertbefore’ and `insertafter’ will be ignored, and if the `regexp’ doesn’t match anywhere in the file, the file will be left unchanged. If the `regexp’ does match, the last matching line will be replaced by the expanded line parameter.

        (Choices: yes, no)[Default: no]

– backup

        Create a backup file including the timestamp information so you can get the original file back if you somehow clobbered it incorrectly.

        (Choices: yes, no)[Default: no]

– create

        Used with `state=present’. If specified, the file will be created if it does not already exist. By default it will fail if the file is missing.

        (Choices: yes, no)[Default: no]

= dest

        The file to modify.

– group

        name of the group that should own the file/directory, as would be fed to `chown’

        [Default: None]

– insertafter

        Used with `state=present’. If specified, the line will be inserted after the last match of specified regular expression. A special value is available; `EOF’ for inserting the line at the end of the file. If specified regular expression has no matches, EOF will be used instead. May not be used with `backrefs’.

        (Choices: EOF, *regex*)[Default: EOF]

– insertbefore

        Used with `state=present’. If specified, the line will be inserted before the last match of specified regular expression. A value is available; `BOF’ for inserting the line at the beginning of the file. If specified regular expression has no matches, the line will be inserted at the end of the file.  May not be used with `backrefs’.

        (Choices: BOF, *regex*)[Default: (null)]

– line

        Required for `state=present’. The line to insert/replace into the file. If `backrefs’ is set, may contain backreferences that will get expanded with the `regexp’ capture groups if the regexp matches.

        [Default: (null)]

– mode

        mode the file or directory should be. For those used to `/usr/bin/chmod’ remember that modes are actually octal numbers (like 0644). Leaving off the leading zero will likely have unexpected results. As of version 1.8, the mode may

        be specified as a symbolic mode (for example, `u+rwx’ or `u=rw,g=r,o=r’).

        [Default: None]

– others

        All arguments accepted by the [file] module also work here.

        [Default: (null)]

– owner

        name of the user that should own the file/directory, as would be fed to `chown’

        [Default: None]

– regexp

        The regular expression to look for in every line of the file. For `state=present’, the pattern to replace if found;

        only the last line found will be replaced. For `state=absent’, the pattern of the line to remove.  Uses Python regular expressions; see http://docs.python.org/2/library/re.html.

        [Default: (null)]

– selevel

        level part of the SELinux file context. This is the MLS/MCS attribute, sometimes known as the `range’. `_default’

        feature works as for `seuser’.

        [Default: s0]

– serole

        role part of SELinux file context, `_default’ feature works as for `seuser’.

        [Default: None]

– setype

        type part of SELinux file context, `_default’ feature works as for `seuser’.

        [Default: None]

– seuser

        user part of SELinux file context. Will default to system policy, if applicable. If set to `_default’, it will use the `user’ portion of the policy if available

        [Default: None]

– state

        Whether the line should be there or not.

        (Choices: present, absent)[Default: present]

– unsafe_writes

        Normally this module uses atomic operations to prevent data corruption or inconsistent reads from the target files, sometimes systems are configured or just broken in ways that prevent this. One example are docker mounted files, they cannot be updated atomically and can only be done in an unsafe manner.

        This boolean option allows ansible to fall back to unsafe methods of updating files for those cases in which you do not have any other choice. Be aware that this is subject to race conditions and can lead to data corruption.

        [Default: False]

– validate

        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 example below. The command is passed securely so shell features like expansion and pipes won’t work.

ansible版本如下

图片 1

实例

下面用修改防火墙文件来举例,学习最常见的修改需求

/etc/sysconfig/iptables文件如下:

图片 2

 

变量

TOMCAT_PORT=6000 

1、需求:替换匹配的目标值

在文件”dest”中,用正则表达式匹配“regexp”值:

若匹配到“regexp”值=1:替换“regexp”值所在行为 “line”;

若匹配到“regexp”值>1:只替换最后一个匹配的有效值;

若匹配到“regexp”值=0:检查是否存在“backrefs”,并且值等于yes,若是则不做任何操作;否则在文件末尾新增行“line”;

– name: Lineinfile-iptables

  lineinfile:

    dest: /etc/sysconfig/iptables

    regexp: "ruler:other start"

line: "{{item.line}}"

backrefs: yes

  with_items:

    – { line: ‘-A INPUT -p tcp -m multiport –dports {{TOMCAT_PORT}} -j ACCEPT’}

第一次运行

 图片 3

 

第二次运行

 图片 4

 

第三次运行由于存在“backrefs: yes”,故结果同第二次一样。

2、需求:在匹配值之前增加行

 

在文件”dest”中,故意设定regexp匹配不到,然后匹配“insertbefore”文本:

若匹配到“insertbefore”值=1:匹配“insertbefore”值之前的行,精确匹配行“line”;若匹配行“line”到,不做任何操作;若未匹配到,则在“insertbefore”值之前增加行“line”。

若匹配到“insertbefore”值>1:则只有最后一个“insertbefore”值为有效匹配值,其余同上。

– name: Lineinfile-iptables

  lineinfile:

dest: /etc/sysconfig/iptables

regexp: "ruler:other start"

    line: "{{item.line}}"

insertbefore: "ruler:other end"

backrefs: yes

  with_items:

    – { line: ‘-A INPUT -p tcp -m multiport –dports {{TOMCAT_PORT}} -j ACCEPT’}

 图片 5

3、需求:在匹配值之后增加行

在文件”dest”中,故意设定regexp匹配不到,然后匹配“insertafter”文本:

若匹配到“insertafter”值=1:匹配“insertafter”值之前的行,精确匹配行“line”;若匹配行“line”到,不做任何操作;若未匹配到,则在“insertafter”值之前增加行“line”。

若匹配到“insertafter”值>1:则只有最后一个“insertafter”值为有效匹配值,其余同上。

– name: Lineinfile-iptables

  lineinfile:

dest: /etc/sysconfig/iptables

regexp: "ruler:other start"

    line: "{{item.line}}"

insertafter: " ruler:other start"

backrefs: yes

  with_items:

    – { line: ‘-A INPUT -p tcp -m multiport –dports {{TOMCAT_PORT}} -j ACCEPT’}

 图片 6

注意:如果不加regexp和backrefs项,那么当匹配insertafter的时候,如果匹配到就在前面新增line,如果匹配不到就会在文件末尾新增line(一般这种情况不是我们所希望的)

4、需求:匹配到就替换行,未匹配到就新增行

优先匹配“regexp”,若匹配到则直接替换为“line”,未匹配到则分成下面的情况

①   存在backrefs: yes 参数:

A匹配“insertbefore”文本或者“insertafter”文本,若都未匹配到,则不会做任何操作。

B匹配到“insertbefore”文本(匹配多个最后一个有效),会从“insertbefore”文本往前匹配“line”,若匹配不到则新增行“line”,否则不做任何操作。

C匹配到“insertafter”文本(匹配多个最后一个有效),会从“insertafter”文本往后匹配“line”,若匹配不到则新增行“line”,否则不做任何操作。

②   不存在backrefs: yes 参数:

A匹配“insertbefore”文本或者“insertafter”文本,若都未匹配到,则在文件末尾新增行“line”。

B匹配到“insertbefore”文本(匹配多个最后一个有效),直接在“insertbefore”文本前面新增行“line”。

C匹配到“insertafter”文本(匹配多个最后一个有效),直接在“insertafter”文本后面新增行“line”。

– name: Lineinfile-iptables

  lineinfile:

    dest: /etc/sysconfig/iptables

    regexp: "ruler:other start"

    line: "{{item.line}}"

    insertbefore: "ruler:other end"

#    insertafter: "ruler:other start"

    backrefs: yes

  with_items:

    – { line: ‘-A INPUT -p tcp -m multiport –dports {{TOMCAT_PORT}} -j ACCEPT’}

第一次运行

 图片 7

第二次运行

 图片 8

当存在backrefs: yes,第三次运行结果与第二次一样

 图片 9

当不存在backrefs: yes,第三次运行结果

 

 图片 10

注意:如果不加regexp和backrefs项,那么当匹配insertbefore的时候,如果匹配到就在前面新增line,如果匹配不到就会在文件末尾新增line(一般这种情况不是我们所希望的)

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