URLs: http->https, plus update some changed/unavailable

AUTHORS

@@ -1,9 +1,9 @@
 The Software Carpentry lesson on the computational algebra system
-[GAP](http://www.gap-system.org) has been developed by Olexandr Konovalov
+[GAP](https://www.gap-system.org) has been developed by Olexandr Konovalov
 (obk1 at st-andrews.ac.uk) for Software Carpentry workshops
 forming a part of the annual CoDiMa Training Schools in Computational
-Discrete Mathematics (http://www.codima.ac.uk/schools/). The development
-has been supported by the CoDiMa CCP (EP/M022641/1).
+Discrete Mathematics (https://blogs.cs.st-andrews.ac.uk/codima/training/).
+The development has been supported by the CoDiMa CCP (EP/M022641/1).
 
 The template for Software Carpentry lessons has its own list of authors
 available at https://github.com/swcarpentry/styles/graphs/contributors.

CONTRIBUTING.md

@@ -47,7 +47,7 @@ and to meet some of our community members.
 
 1.  If you wish to change this lesson,
     please work in <https://github.com/carpentries-incubator/gap-lesson/>,
-    which can be viewed at <http://carpentries-incubator.github.io/gap-lesson/>.
+    which can be viewed at <https://carpentries-incubator.github.io/gap-lesson/>.
 
 2.  If you wish to change the example lesson,
     please work in <https://github.com/carpentries/lesson-example>,
@@ -137,16 +137,16 @@ You can also [reach us by email][contact].
 
 [contact]: mailto:[email protected]
 [dc-issues]: https://github.com/issues?q=user%3Adatacarpentry
-[dc-lessons]: http://datacarpentry.org/lessons/
-[dc-site]: http://datacarpentry.org/
-[discuss-list]: http://lists.software-carpentry.org/listinfo/discuss
+[dc-lessons]: https://datacarpentry.org/lessons/
+[dc-site]: https://datacarpentry.org/
+[discuss-list]: https://lists.software-carpentry.org/listinfo/discuss
 [example-site]: https://carpentries.github.io/lesson-example
-[github]: http://github.com
+[github]: https://github.com
 [github-flow]: https://guides.github.com/introduction/flow/
 [github-join]: https://github.com/join
 [how-contribute]: https://egghead.io/series/how-to-contribute-to-an-open-source-project-on-github
 [issues]: https://github.com/carpentries-incubator/gap-lesson/issues/
 [repo]: https://github.com/carpentries-incubator/gap-lesson/
 [swc-issues]: https://github.com/issues?q=user%3Aswcarpentry
-[swc-lessons]: http://software-carpentry.org/lessons/
-[swc-site]: http://software-carpentry.org/
+[swc-lessons]: https://software-carpentry.org/lessons/
+[swc-site]: https://software-carpentry.org/

LICENSE.md

@@ -26,7 +26,7 @@ Under the following terms:
 * **Attribution**---You must give appropriate credit (mentioning that
   your work is derived from work that is Copyright © Software
   Carpentry and, where practical, linking to
-  http://software-carpentry.org/), provide a [link to the
+  https://software-carpentry.org/), provide a [link to the
   license][cc-by-human], and indicate if changes were made. You may do
   so in any reasonable manner, but not in any way that suggests the
   licensor endorses you or your use.
@@ -79,5 +79,5 @@ are registered trademarks of [Community Initiatives][CI].
 [cc-by-human]: https://creativecommons.org/licenses/by/4.0/
 [cc-by-legal]: https://creativecommons.org/licenses/by/4.0/legalcode
 [mit-license]: https://opensource.org/licenses/mit-license.html
-[ci]: http://communityin.org/
+[ci]: https://communityin.org/
 [osi]: https://opensource.org

README.md

@@ -1,10 +1,10 @@
 [![DOI](https://zenodo.org/badge/DOI/10.5281/zenodo.597073.svg)](https://doi.org/10.5281/zenodo.597073)
 
-This is the Carpentries-style lesson on the computational algebra system [GAP](http://www.gap-system.org).
+This is the Carpentries-style lesson on the computational algebra system [GAP](https://www.gap-system.org).
 
 Its development was started by Olexandr Konovalov for the Software Carpentry
 workshop organised as a part of the [First CoDiMa Training School in Computational
-Discrete Mathematics](http://www.codima.ac.uk/school2015/) in 2015. Since then, it
+Discrete Mathematics](https://blogs.cs.st-andrews.ac.uk/codima/school2015/) in 2015. Since then, it
 has had several releases, produced in collaboration with further contributors, and has
 been taught by different instructors at more than ten different events, the full list
 of which is available on the GAP lesson wiki
@@ -30,9 +30,9 @@ to which you are welcome to contribute following the guidelines
 This lesson is published on Zenodo [here](https://doi.org/10.5281/zenodo.597073).
 To cite it, please use the format suggested there.
 
-We acknowledge financial support from [CCP-CoDiMa](https://www.codima.ac.uk/)
+We acknowledge financial support from [CCP-CoDiMa](https://blogs.cs.st-andrews.ac.uk/codima/)
 (Collaborative Computational Project in the area of Computational Discrete Mathematics
-[EP/M022641/1](http://gow.epsrc.ac.uk/NGBOViewGrant.aspx?GrantRef=EP/M022641/1))
-and from [OpenDreamKit](http://opendreamkit.org/) [Horizon 2020](https://ec.europa.eu/programmes/horizon2020/)
+EP/M022641/1 and from the [OpenDreamKit](https://opendreamkit.org/)
+[Horizon 2020](https://ec.europa.eu/programmes/horizon2020/)
 [European Research Infrastructures](https://ec.europa.eu/programmes/horizon2020/en/h2020-section/european-research-infrastructures-including-e-infrastructures)
-project (#<a href="http://cordis.europa.eu/project/rcn/198334_en.html">676541</a>).
+project (#<a href="https://cordis.europa.eu/project/rcn/198334_en.html">676541</a>).

_config.yml

@@ -24,7 +24,7 @@ repository: <USERNAME>/<PROJECT>
 
 # Sites.
 amy_site: "https://amy.software-carpentry.org/workshops"
-dc_site: "http://datacarpentry.org"
+dc_site: "https://datacarpentry.org"
 swc_github: "https://github.com/swcarpentry"
 swc_site: "https://software-carpentry.org"
 swc_pages: "https://swcarpentry.github.io"

_episodes/01-command-line.md

@@ -21,7 +21,7 @@ keypoints:
 - "Read 'A First Session with GAP' from the GAP Tutorial."
 ---
 
-If GAP is installed correctly you should be able to start it. Exactly how 
+If GAP is installed correctly you should be able to start it. Exactly how
 you start GAP will depend on your operating system and how you installed
 GAP. GAP starts with the *banner* displaying information about the version of
 the system and loaded components, and then displays the command line prompt
@@ -33,15 +33,15 @@ the system and loaded components, and then displays the command line prompt
  └───────┘   Architecture: x86_64-apple-darwin16.7.0-default64
  Configuration:  gmp 6.1.2, readline
  Loading the library and packages ...
- Packages:   AClib 1.3, Alnuth 3.1.0, AtlasRep 1.5.1, AutPGrp 1.9, 
-             Browse 1.8.8, CRISP 1.4.4, Cryst 4.1.17, CrystCat 1.1.8, 
-             CTblLib 1.2.2, FactInt 1.6.2, FGA 1.4.0, GAPDoc 1.6.1, IO 4.5.1, 
-             IRREDSOL 1.4, LAGUNA 3.9.0, Polenta 1.3.8, Polycyclic 2.14, 
-             PrimGrp 3.3.1, RadiRoot 2.8, ResClasses 4.7.1, SmallGrp 1.3, 
-             Sophus 1.24, SpinSym 1.5, TomLib 1.2.6, TransGrp 2.0.2, 
+ Packages:   AClib 1.3, Alnuth 3.1.0, AtlasRep 1.5.1, AutPGrp 1.9,
+             Browse 1.8.8, CRISP 1.4.4, Cryst 4.1.17, CrystCat 1.1.8,
+             CTblLib 1.2.2, FactInt 1.6.2, FGA 1.4.0, GAPDoc 1.6.1, IO 4.5.1,
+             IRREDSOL 1.4, LAGUNA 3.9.0, Polenta 1.3.8, Polycyclic 2.14,
+             PrimGrp 3.3.1, RadiRoot 2.8, ResClasses 4.7.1, SmallGrp 1.3,
+             Sophus 1.24, SpinSym 1.5, TomLib 1.2.6, TransGrp 2.0.2,
              utils 0.54
  Try '??help' for help. See also '?copyright', '?cite' and '?authors'
-gap> 
+gap>
 ~~~
 {: .output}
 
@@ -135,7 +135,7 @@ Up and Down arrow keys after that, to scroll only the lines that begin with
 the same string.
 
 If you want to store a value for later use, you can assign it to a name
-using `:=` 
+using `:=`
 
 ~~~
 universe := 6*7;
@@ -299,7 +299,7 @@ The way functions are named in GAP will hopefully help you to memorise or even g
 of library functions. If a variable name consists of several words then the
 first letter of each word is capitalised (remember that GAP is case-sensitive!).
 Further details on naming conventions used in GAP are documented in the GAP
-manual [here](http://www.gap-system.org/Manuals/doc/ref/chap5.html#X81F732457F7BC851).
+manual [here](https://www.gap-system.org/Manuals/doc/ref/chap5.html#X81F732457F7BC851).
 Functions with names in `ALL_CAPITAL_LETTERS` are internal functions not intended
 for general use. Use them with extreme care!
 
@@ -477,7 +477,7 @@ gap> elts[1]; elts[3]; Length(elts);
 > * Not required to contain objects of the same type
 >
 >
-> * See more in [GAP Tutorial: Lists and Records](http://www.gap-system.org/Manuals/doc/tut/chap3.html)
+> * See more in [GAP Tutorial: Lists and Records](https://www.gap-system.org/Manuals/doc/tut/chap3.html)
 {: .callout}
 
 Many functions in GAP refer to `Set`s. A set in GAP is just a list that happens to have

_episodes/04-testing.md

@@ -65,7 +65,7 @@ together with one or more lines starting with `#`, are considered as comments.
 All other lines are interpreted as GAP output from the preceding GAP input.
 
 To run the test, one should use the function `Test`, as documented
-[here](http://www.gap-system.org/Manuals/doc/ref/chap7.html#X87712F9D8732193C).
+[here](https://www.gap-system.org/Manuals/doc/ref/chap7.html#X87712F9D8732193C).
 For example (assuming that the function `AvgOrdOfGroup` is already loaded):
 
 ~~~

_episodes/05-small-groups.md

@@ -19,8 +19,8 @@ In this section, we wish to discover some non-trivial groups with an interesting
 property: namely, that the average order of their elements is an integer.
 
 The GAP distribution includes a number of data libraries (see an overview
-[here](http://www.gap-system.org/Datalib/datalib.html)). One of them is
-the [Small Groups Library](http://www.gap-system.org/Packages/sgl.html) by
+[here](https://www.gap-system.org/Datalib/datalib.html)). One of them is
+the [Small Groups Library](https://www.gap-system.org/Packages/sgl.html) by
 Hans Ulrich Besche, Bettina Eick and Eamonn O'Brien.
 
 This library provides various utilities to determine which information
@@ -228,7 +228,7 @@ TestAllOrders(TestOneGroup,128);
 {: .output}
 
 To explore it further, we can get its `StructureDescription` (see
-[here](http://www.gap-system.org/Manuals/doc/ref/chap39.html#X87BF1B887C91CA2E)
+[here](https://www.gap-system.org/Manuals/doc/ref/chap39.html#X87BF1B887C91CA2E)
 for the explanation of the notation it uses):
 
 ~~~
@@ -461,7 +461,7 @@ gap> TestOneOrderVariadic(IsIntegerAverageOrder,357);
 
 Of course, this now introduces some complication for the test file,
 which compares the actual output with the reference output. To resolve
-this problem, we will decide to run the tests at info level 0 to suppress  
+this problem, we will decide to run the tests at info level 0 to suppress
 all additional outputs. Because the tests may have been started in the
 GAP session with a different info level, we will remember that info level
 to restore it after the test:

_extras/discuss.md

@@ -13,7 +13,7 @@ are three different identifiers. A call to `SymmetricGroup(3)` works, but
 2. An error message **`“Error, Variable: 'FuncName' must have a value”`** in a
 function call usually points to a typo in the function name (see the previous hint),
 or to some package that must be loaded in advance using
-[**`LoadPackage`**](http://www.gap-system.org/Manuals/doc/ref/chap76.html#X79B373A77B29D1F5).
+[**`LoadPackage`**](https://www.gap-system.org/Manuals/doc/ref/chap76.html#X79B373A77B29D1F5).
 
 3. **Do not hesitate to use longer and more informative variable names where
 appropriate.** For example, `x` looks perfectly suitable for `List([1..10], x -> x^2)`,
@@ -33,17 +33,17 @@ in the GAP manuals, but also in the manuals of all GAP packages available
 in your GAP installation.
 
 7. **Set default help format to HTML.** Use
-[**`SetHelpViewer`**](http://www.gap-system.org/Manuals/doc/ref/chap2.html#X87C1BFB2826488B0)
+[**`SetHelpViewer`**](https://www.gap-system.org/Manuals/doc/ref/chap2.html#X87C1BFB2826488B0)
 to view it with your preferred browser.
 
-8. **Use [**`LogTo`**](http://www.gap-system.org/Manuals/doc/ref/chap9.html#X79813A6686894960)
+8. **Use [**`LogTo`**](https://www.gap-system.org/Manuals/doc/ref/chap9.html#X79813A6686894960)
 to save all GAP input and output into a text file.** It should be called before
 calculations, not after!
 
 9. **If the calculation takes too long, press `<Control>-C` to interrupt it**.
 Then type quit; to leave the break loop.
 
-10. **Read [A First Session with GAP](http://www.gap-system.org/Manuals/doc/tut/chap2.html)**
+10. **Read [A First Session with GAP](https://www.gap-system.org/Manuals/doc/tut/chap2.html)**
 from the GAP Tutorial.
 
 
@@ -52,24 +52,24 @@ from the GAP Tutorial.
 * Use direct calculations in the command line for object exploration and prototyping,
 then think how to organise your code to make it reusable.
 
-* Use [**`LogTo`**](http://www.gap-system.org/Manuals/doc/ref/chap9.html#X79813A6686894960)
+* Use [**`LogTo`**](https://www.gap-system.org/Manuals/doc/ref/chap9.html#X79813A6686894960)
 to save inputs and outputs to a logfile which then you can edit in a text editor.
 
 * Save code in text files and use
-[**`Read`**](http://www.gap-system.org/Manuals/doc/ref/chap9.html#X8373AC6B7D5F9167)
+[**`Read`**](https://www.gap-system.org/Manuals/doc/ref/chap9.html#X8373AC6B7D5F9167)
 to load them. Find some advanced text editor to edit these files.
 
 * Make your code modular and reusable by organising it into functions.
 
 * Write comments in the code – this will help you when you will return to it after a while.
 
-* Understand [break loops](http://www.gap-system.org/Manuals/doc/ref/chap6.html#X8593B49F8705B486):
-you may [explore variables](http://www.gap-system.org/Manuals/doc/ref/chap6.html#X7EE5CF2C8419F061)
+* Understand [break loops](https://www.gap-system.org/Manuals/doc/ref/chap6.html#X8593B49F8705B486):
+you may [explore variables](https://www.gap-system.org/Manuals/doc/ref/chap6.html#X7EE5CF2C8419F061)
 on the current break level and use
-[**`Where`**](http://www.gap-system.org/Manuals/doc/ref/chap6.html#X7A7FFA2B7C1EF5A3)
+[**`Where`**](https://www.gap-system.org/Manuals/doc/ref/chap6.html#X7A7FFA2B7C1EF5A3)
 to show the last commands before the error occurred.
 
-* Use [preferences mechanism](http://www.gap-system.org/Manuals/doc/ref/chap3.html#X7FD66F977A3B02DF)
+* Use [preferences mechanism](https://www.gap-system.org/Manuals/doc/ref/chap3.html#X7FD66F977A3B02DF)
 to customise GAP, for example, to set help viewer to HTML or to make command line history available
 after quitting GAP in the next GAP session.
 
@@ -106,34 +106,32 @@ For example:
     * Representation matters: it may be worth to convert a group from fp group
       to an isomorphic pc group or a permutation group to use faster methods.
 
-* See [GAP Frequently Asked Questions](http://www.gap-system.org/Faq/faq.html) for further hints.
+* See [GAP Frequently Asked Questions](https://www.gap-system.org/Faq/faq.html) for further hints.
 
 ## Stay in touch
 
-* Subscribe to the **[GAP Forum](http://mail.gap-system.org/mailman/listinfo/forum)**.
-
-* If you are on Twitter, follow **[gap_system](https://twitter.com/gap_system)**.
+* Subscribe to the **[GAP Forum](https://www.gap-system.org/Contacts/Forum/forum.html)**.
 
 * If you need help, choose among these three options, dependently on the question:
 
-    * ask questions in the [GAP Forum](http://www.gap-system.org/Contacts/Forum/forum.html)
+    * ask questions in the [GAP Forum](https://www.gap-system.org/Contacts/Forum/forum.html)
 
-    * send them to the [GAP Support](http://www.gap-system.org/Contacts/People/supportgroup.html)
+    * send them to the [GAP Support](https://www.gap-system.org/Contacts/People/supportgroup.html)
 
-    * post them at the [Mathematics Q&A site](http://math.stackexchange.com/questions/tagged/gap?sort=frequent&pageSize=50)
+    * post them at the [Mathematics Q&A site](https://math.stackexchange.com/questions/tagged/gap?sort=frequent&pageSize=50)
 
 
 ## Contributing to GAP
 
 * If you think that you’ve found a bug: please
 [create an issue on GitHub](https://github.com/gap-system/gap/issues) or
-report it by email to [GAP Support](http://www.gap-system.org/Contacts/People/supportgroup.html).
+report it by email to [GAP Support](https://www.gap-system.org/Contacts/People/supportgroup.html).
 
 * Please cite GAP if you use it. This helps for the community to grow,
 and this will help you in return.
-[This page](http://www.gap-system.org/Contacts/cite.html)
+[This page](https://www.gap-system.org/Contacts/cite.html)
 suggests how to cite GAP, and the function
-[**`Cite`**](http://www.gap-system.org/Manuals/doc/ref/chap76.html#X79637D9A7B1AD7F7)
+[**`Cite`**](https://www.gap-system.org/Manuals/doc/ref/chap76.html#X79637D9A7B1AD7F7)
 will help to generate citation sample for precisely the same version of GAP that is used.
 
 * Consider sharing your GAP developments with others, from sharing your code by
@@ -194,7 +192,7 @@ if this option is not possible?
 
 `ReadCSV( filename[, nohead][, separator] )` reads a file in a CSV (comma
 separated values) format and returns its entries as a list of records
-(see [here](http://www.gap-system.org/Manuals/doc/ref/chap10.html#X848DD7DC79363341)).
+(see [here](https://www.gap-system.org/Manuals/doc/ref/chap10.html#X848DD7DC79363341)).
 The entries of the first line of the file will be used for the names
 of the record components (blanks will be translated into underscores).
 One could also indicate that the first line contains data instead of
@@ -203,16 +201,16 @@ may be used to output CSV files.
 
 To read arbitrary (binary or text) files as strings, use the `StringFile`
 function provided by the GAPDoc package (see
-[here](http://www.gap-system.org/Manuals/pkg/GAPDoc-1.5.1/doc/chap6.html#X7E14D32181FBC3C3)).
+[here](https://www.gap-system.org/Manuals/pkg/GAPDoc-1.5.1/doc/chap6.html#X7E14D32181FBC3C3)).
 It will return the content of the file as a string.
 After that, you may use various string manipulation tools (see
-[Strings and Characters](http://www.gap-system.org/Manuals/doc/ref/chap27.html)
+[Strings and Characters](https://www.gap-system.org/Manuals/doc/ref/chap27.html)
 in the GAP reference manual) to process it in the way you need. GAPDoc package
 also provides the `FileString` function which writes the content of a string
 into a file.
 
 If you need to organise reading/writing line by line, instead of reading or
 writing the whole file/string at once, we suggest to look at the functionality
 provided by the IO package
-(see [here](http://www.gap-system.org/Manuals/pkg/io-4.4.6/doc/chap4.html)),
+(see [here](https://www.gap-system.org/Manuals/pkg/io-4.4.6/doc/chap4.html)),
 in particular at `IO_ReadLine` and `IO_WriteLine`.

_extras/guide.md

@@ -66,10 +66,6 @@ package is not compiled.
 
 * Explain how to switch to view HTML version of the Manual with MathJax support.
 
-* Give a hint that the sitemap on the [GAP website](http://www.gap-system.org)
-shows the [Search the GAP web site](http://www.gap-system.org/search.html) page
-which allows some specific search requests.
-
 * Draw attention to the difference between `AsList` and `AsSSortedList`.
 
 * Help to call `WriteGapIniFile` and customise GAP e.g. to use browser as a
@@ -100,10 +96,10 @@ results in a no-method-found error. This may be a good moment to introduce
 this special kind of error messages.
 
 * For extending GAP with new types of objects, refer to
-[Creating New Objects](http://www.gap-system.org/Manuals/doc/ref/chap79.html)
-and [Examples of Extending the System](http://www.gap-system.org/Manuals/doc/ref/chap80.html)
+[Creating New Objects](https://www.gap-system.org/Manuals/doc/ref/chap79.html)
+and [Examples of Extending the System](https://www.gap-system.org/Manuals/doc/ref/chap80.html)
 of the GAP Reference Manual.
-Also, the [Circle package](http://www.gap-system.org/Packages/circle.html)
+Also, the [Circle package](https://www.gap-system.org/Packages/circle.html)
 provides an example of extending GAP with new multiplicative objects.
 
 1.  Solution of the challenge:
@@ -119,7 +115,7 @@ provides an example of extending GAP with new multiplicative objects.
 message.
 
 
-## [Using regression tests]({% link _episodes/01-command-line.md %})
+## [Using regression tests]({% link _episodes/01-command-line.md %})(04-testing.html)
 
 * Learners may need help with formatting the test because of misplaced comments
 and/or different formatting of the output.