# Regexp failure: Unmatched group **URL:** \ **Category:** Ansible Project\ **Created:** [November 5, 2018, 8:56pm UTC](https://forum.ansible.com/t/regexp-failure-unmatched-group/28947 "2018-11-05T20:56:31Z")\ **Posts on this page:** 6\ **Page:** 1
**Author:** ![John\_Harmon](https://avatars.discourse-cdn.com/v4/letter/j/edb3f5/32.png) [@John\_Harmon](https://forum.ansible.com/u/John_Harmon)\ **Post date:** [November 5, 2018, 8:56pm UTC](https://forum.ansible.com/t/regexp-failure-unmatched-group/28947/1 "2018-11-05T20:56:31Z")
I am getting a failure with the latter half of my task. I replaced the working stuff with … According to a regexp tester, every group does have something, and I don’t have empty groups. [https://regex101.com/r/MNkwaD/1](https://regex101.com/r/MNkwaD/1) I changed stdout\_callback to minimal, but it didn’t look much different. I am so new to regexp I could use another pair of eyes. I don’t know what else to look for here. Code: ` - name: Sanitize vm.cfg step 2 of 2 lineinfile: path: “{{ file }}” regexp: “{{ item.regexp }}” line: “{{ item.line }}” backrefs: “{{ item.backrefs }}” with\_items: … - regexp: (^disk\W+[)?(‘file:[^’]+‘(,)?)?(‘phy:[^’]+’(,)?)?(])? line: \1\2\3\6 backrefs: yes ` Failure: ` failed: [ovmftp] (item={u’regexp’: u"(^disk\W+\[)?(‘file:[^’]+‘(,)?)?(‘phy:[^’]+’(,)?)?(])?", u’line’: u’\1\2\3\6\5\4’, u’backrefs’: True}) =\> {“changed”: false, “item”: {“backrefs”: true, “line”: “\1\2\3\6\5\4”, “regexp”: “(^disk\W+\[)?(‘file:[^’]+‘(,)?)?(‘phy:[^’]+’(,)?)?(])?”}, “module\_stderr”: “tput: No value for $TERM and no -T specified\ntput: No value for $TERM and no -T specified\nTraceback (most recent call last):\n File "", line 113, in \n File "", line 105, in \_ansiballz\_main\n File "", line 48, in invoke\_module\n File "/tmp/ansible\_lineinfile\_payload\_Wm2J\_Z/ **main**.py", line 520, in \n File "/tmp/ansible\_lineinfile\_payload\_Wm2J\_Z/ **main**.py", line 511, in main\n File "/tmp/ansible\_lineinfile\_payload\_Wm2J\_Z/ **main**.py", line 300, in present\n File "/usr/lib64/python2.7/re.py", line 266, in \_expand\n return sre\_parse.expand\_template(template, match)\n File "/usr/lib64/python2.7/sre\_parse.py", line 800, in expand\_template\n raise error, "unmatched group"\nsre\_constants.error: unmatched group\n”, “module\_stdout”: “”, “msg”: “MODULE FAILURE\nSee stdout/stderr for the exact error”, “rc”: 1} ` ---
**Author:** ![Kai\_Stian\_Olstad](https://avatars.discourse-cdn.com/v4/letter/k/e19adc/32.png) [@Kai\_Stian\_Olstad](https://forum.ansible.com/u/Kai_Stian_Olstad)\ **Post date:** [November 5, 2018, 9:23pm UTC](https://forum.ansible.com/t/regexp-failure-unmatched-group/28947/2 "2018-11-05T21:23:17Z")
So you have a regexp that isn't working, but haven't told us what you are trying to do, so it's actually impossible to help you. ---
**Author:** ![John\_Harmon](https://avatars.discourse-cdn.com/v4/letter/j/edb3f5/32.png) [@John\_Harmon](https://forum.ansible.com/u/John_Harmon)\ **Post date:** [November 5, 2018, 9:28pm UTC](https://forum.ansible.com/t/regexp-failure-unmatched-group/28947/3 "2018-11-05T21:28:29Z")
> So you have a regexp that isn’t working, but haven’t told us what you are trying to do, so it’s actually impossible to help you. > > – > Kai Stian Olstad In the link I provided there is a sample string. I capture 6 different groups. In short, I am trying to remove all phy devices strings from the line. From my line, you can see I am trying to only retain groups 1,2,3 and 6. When complete, I should have a new “disk = ['file…]” string that only contains devices being referenced by a file instead of a physical device. My apologies that I wasn’t more clear. ---
**Author:** ![Kai\_Stian\_Olstad](https://avatars.discourse-cdn.com/v4/letter/k/e19adc/32.png) [@Kai\_Stian\_Olstad](https://forum.ansible.com/u/Kai_Stian_Olstad)\ **Post date:** [November 5, 2018, 10:35pm UTC](https://forum.ansible.com/t/regexp-failure-unmatched-group/28947/4 "2018-11-05T22:35:05Z")
If you that is the only place you have phy: replace module would be a lot easier.   - replace:       path: /path/to/file       regexp: (, )?'phy:[^']+'       replace: '' ---
**Author:** ![John\_Harmon](https://avatars.discourse-cdn.com/v4/letter/j/edb3f5/32.png) [@John\_Harmon](https://forum.ansible.com/u/John_Harmon)\ **Post date:** [November 5, 2018, 10:42pm UTC](https://forum.ansible.com/t/regexp-failure-unmatched-group/28947/5 "2018-11-05T22:42:24Z")
> If you that is the only place you have phy: replace module would be a lot easier. > > - replace: > path: /path/to/file > regexp: (, )?‘phy:[^’]+’ > replace: ‘’ > > – > Kai Stian Olstad Yep, you are right. That is much easier. I’ll go that route. Out of curiosity do you think it is a syntax issue with my hodgepodge of groups causing the “unmatched group” error? or a bug? ---
**Author:** ![Kai\_Stian\_Olstad](https://avatars.discourse-cdn.com/v4/letter/k/e19adc/32.png) [@Kai\_Stian\_Olstad](https://forum.ansible.com/u/Kai_Stian_Olstad)\ **Post date:** [November 6, 2018, 12:19pm UTC](https://forum.ansible.com/t/regexp-failure-unmatched-group/28947/6 "2018-11-06T12:19:24Z")
I don't think it's a bug, more in the line it's impossible or at least very hard to write regexp to cover that string.