Systematic check of all URLs

- fix "uninformative link text" warnings
- update to the modern GAP website structure
- update several links to GAP package websites

README.md

@@ -22,13 +22,14 @@ so that we can add it to the list at the GAP lesson wiki
 submit it to the [issue tracker](https://github.com/carpentries-incubator/gap-lesson/issues)
 or send by email to [[email protected]](mailto:[email protected]). We also
 encourage you to collect and share the feedback using
-[sticky notes as minute cards](https://carpentries.github.io/instructor-training/06-feedback/index.html)
+[sticky notes as minute cards](https://carpentries.github.io/instructor-training/06-feedback.html#minute-cards)
 (in full or in the form of a summary). This will help us in further lesson development,
 to which you are welcome to contribute following the guidelines
 [here](https://github.com/carpentries-incubator/gap-lesson/blob/gh-pages/CONTRIBUTING.md).
 
-This lesson is published on Zenodo [here](https://doi.org/10.5281/zenodo.597073).
-To cite it, please use the format suggested there.
+This lesson is published on Zenodo [DOI 10.5281/zenodo.597073](https://doi.org/10.5281/zenodo.597073).
+To cite it, please use the format suggested in the
+[CITATION file](https://github.com/carpentries-incubator/gap-lesson/blob/main/CITATION).
 
 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

episodes/01-command-line.md

@@ -273,8 +273,8 @@ or `NaturalHomomorphismByNormalSubgroup` using completion.
 The way functions are named in GAP will hopefully help you to memorise or even guess names
 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](https://www.gap-system.org/Manuals/doc/ref/chap5.html#X81F732457F7BC851).
+Further details on naming conventions used in GAP are documented
+[in the GAP manual here](https://docs.gap-system.org/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!
 
@@ -438,7 +438,7 @@ gap> elts[1]; elts[3]; Length(elts);
 
 - Not required to contain objects of the same type
 
-- See more in [GAP Tutorial: Lists and Records](https://www.gap-system.org/Manuals/doc/tut/chap3.html)
+- See more in [GAP Tutorial: Lists and Records](https://docs.gap-system.org/doc/tut/chap3.html)
 
 
 ::::::::::::::::::::::::::::::::::::::::::::::::::

episodes/04-testing.md

@@ -66,8 +66,8 @@ lines at the beginning of the test file that start with `#`, and one empty line
 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](https://www.gap-system.org/Manuals/doc/ref/chap7.html#X87712F9D8732193C).
+To run the test, one should use the function `Test` (see
+[documentation](https://docs.gap-system.org/doc/ref/chap7.html#X87712F9D8732193C).
 For example (assuming that the function `AvgOrdOfGroup` is already loaded):
 
 ```gap

episodes/05-small-groups.md

@@ -21,9 +21,10 @@ exercises: 15
 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](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
+The GAP distribution includes a number of data libraries
+(for example, search for the word "library" in the
+[list of packages distributed with GAP](https://www.gap-system.org/packages/)).
+One of them is the [Small Groups Library](https://gap-packages.github.io/smallgrp/) by
 Hans Ulrich Besche, Bettina Eick and Eamonn O'Brien.
 
 This library provides various utilities to determine which information
@@ -222,7 +223,7 @@ TestAllOrders(TestOneGroup,128);
 ```
 
 To explore it further, we can get its `StructureDescription` (see
-[here](https://www.gap-system.org/Manuals/doc/ref/chap39.html#X87BF1B887C91CA2E)
+[documentation](https://docs.gap-system.org/doc/ref/chap39.html#X87BF1B887C91CA2E)
 for the explanation of the notation it uses):
 
 ```gap

instructors/instructor-notes.md

@@ -94,10 +94,10 @@ permalink: /guide/
   this special kind of error messages.
 
 - For extending GAP with new types of objects, refer to
-  [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)
+  [Creating New Objects](https://docs.gap-system.org/doc/ref/chap79.html)
+  and [Examples of Extending the System](https://docs.gap-system.org/doc/ref/chap80.html)
   of the GAP Reference Manual.
-  Also, the [Circle package](https://www.gap-system.org/Packages/circle.html)
+  Also, the [Circle package](https://gap-packages.github.io/circle/)
   provides an example of extending GAP with new multiplicative objects.
 
 1. Solution of the challenge:

learners/discuss.md

@@ -12,7 +12,7 @@ permalink: /discuss/
 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`**](https://www.gap-system.org/Manuals/doc/ref/chap76.html#X79B373A77B29D1F5).
+  [**`LoadPackage`**](https://docs.gap-system.org/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)`,
@@ -32,42 +32,42 @@ permalink: /discuss/
   in your GAP installation.
 
 7. **Set default help format to HTML.** Use
-  [**`SetHelpViewer`**](https://www.gap-system.org/Manuals/doc/ref/chap2.html#X87C1BFB2826488B0)
+  [**`SetHelpViewer`**](https://docs.gap-system.org/doc/ref/chap2.html#X87C1BFB2826488B0)
   to view it with your preferred browser.
 
-8. **Use [**`LogTo`**](https://www.gap-system.org/Manuals/doc/ref/chap9.html#X79813A6686894960)
+8. **Use [**`LogTo`**](https://docs.gap-system.org/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](https://www.gap-system.org/Manuals/doc/tut/chap2.html)**
+10. **Read [A First Session with GAP](https://docs.gap-system.org/doc/tut/chap2.html)**
   from the GAP Tutorial.
 
 ## Writing programs in GAP
 
 - 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`**](https://www.gap-system.org/Manuals/doc/ref/chap9.html#X79813A6686894960)
+- Use [**`LogTo`**](https://docs.gap-system.org/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`**](https://www.gap-system.org/Manuals/doc/ref/chap9.html#X8373AC6B7D5F9167)
+  [**`Read`**](https://docs.gap-system.org/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](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)
+- Understand [break loops](https://docs.gap-system.org/doc/ref/chap6.html#X8593B49F8705B486):
+  you may [explore variables](https://docs.gap-system.org/doc/ref/chap6.html#X7EE5CF2C8419F061)
   on the current break level and use
-  [**`Where`**](https://www.gap-system.org/Manuals/doc/ref/chap6.html#X7A7FFA2B7C1EF5A3)
+  [**`Where`**](https://docs.gap-system.org/doc/ref/chap6.html#X7A7FFA2B7C1EF5A3)
   to show the last commands before the error occurred.
 
-- Use [preferences mechanism](https://www.gap-system.org/Manuals/doc/ref/chap3.html#X7FD66F977A3B02DF)
+- Use [preferences mechanism](https://docs.gap-system.org/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.
 
@@ -104,31 +104,31 @@ permalink: /discuss/
   - 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](https://www.gap-system.org/Faq/faq.html) for further hints.
+- See [GAP Frequently Asked Questions](https://www.gap-system.org/faq/) for further hints.
 
 ## Stay in touch
 
-- Subscribe to the **[GAP Forum](https://www.gap-system.org/Contacts/Forum/forum.html)**.
+- Subscribe to the **[GAP Forum](https://www.gap-system.org/forum/)**.
 
 - If you need help, choose among these three options, dependently on the question:
 
-  - ask questions in the [GAP Forum](https://www.gap-system.org/Contacts/Forum/forum.html)
+  - ask questions in the [GAP Forum](https://www.gap-system.org/forum/)
 
-  - send them to the [GAP Support](https://www.gap-system.org/Contacts/People/supportgroup.html)
+  - send them to the [GAP Support](https://www.gap-system.org/issues/)
 
   - 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](https://www.gap-system.org/Contacts/People/supportgroup.html).
+  report it by email to [GAP Support](https://www.gap-system.org/issues/).
 
 - Please cite GAP if you use it. This helps for the community to grow,
   and this will help you in return.
-  [This page](https://www.gap-system.org/Contacts/cite.html)
+  [This page](https://www.gap-system.org/cite/)
   suggests how to cite GAP, and the function
-  [**`Cite`**](https://www.gap-system.org/Manuals/doc/ref/chap76.html#X79637D9A7B1AD7F7)
+  [**`Cite`**](https://docs.gap-system.org/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
@@ -183,7 +183,7 @@ 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](https://www.gap-system.org/Manuals/doc/ref/chap10.html#X848DD7DC79363341)).
+(see [documentation](https://docs.gap-system.org/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
@@ -192,18 +192,18 @@ 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](https://www.gap-system.org/Manuals/pkg/GAPDoc-1.5.1/doc/chap6.html#X7E14D32181FBC3C3)).
+[documentation](https://docs.gap-system.org/pkg/gapdoc/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](https://www.gap-system.org/Manuals/doc/ref/chap27.html)
+[Strings and Characters](https://docs.gap-system.org/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](https://www.gap-system.org/Manuals/pkg/io-4.4.6/doc/chap4.html)),
+(see [documentation](https://docs.gap-system.org/pkg/io/doc/chap4.html)),
 in particular at `IO_ReadLine` and `IO_WriteLine`.
 
 

learners/reference.md

@@ -4,55 +4,55 @@ permalink: /reference/
 
 ## [First session with GAP]({% link \_episodes/01-command-line.md %})
 
-- [GAP Tutorial: A First session with GAP](https://www.gap-system.org/Manuals/doc/tut/chap2.html)
+- [GAP Tutorial: A First session with GAP](https://docs.gap-system.org/doc/tut/chap2.html)
 
-- [GAP Reference Manual: Naming Conventions](https://plus.google.com/events/cfm3tc375c142qtodvlvcfs82l4)
+- [GAP Reference Manual: Naming Conventions](https://docs.gap-system.org/doc/ref/chap5.html#X81F732457F7BC851)
 
-- [GAP Reference Manual: The Help System](https://www.gap-system.org/Manuals/doc/ref/chap2.html)
+- [GAP Reference Manual: The Help System](https://docs.gap-system.org/doc/ref/chap2.html)
 
-- [GAP Tutorial: Lists and Records](https://www.gap-system.org/Manuals/doc/tut/chap3.html)
+- [GAP Tutorial: Lists and Records](https://docs.gap-system.org/doc/tut/chap3.html)
 
-- [GAP Reference Manual: Strings and Characters](https://www.gap-system.org/Manuals/doc/ref/chap27.html)
+- [GAP Reference Manual: Strings and Characters](https://docs.gap-system.org/doc/ref/chap27.html)
 
-- [GAP Reference Manual: The Programming Language](https://www.gap-system.org/Manuals/doc/ref/chap4.html#X7FE7C0C17E1ED118)
+- [GAP Reference Manual: The Programming Language](https://docs.gap-system.org/doc/ref/chap4.html#X7FE7C0C17E1ED118)
 
 ## [Some more GAP objects]({% link \_episodes/02-some-objects.md %})
 
-- [Integers](https://www.gap-system.org/Manuals/doc/ref/chap14.html)
+- [Integers](https://docs.gap-system.org/doc/ref/chap14.html)
 
-- [Rationals](https://www.gap-system.org/Manuals/doc/ref/chap17.html)
+- [Rationals](https://docs.gap-system.org/doc/ref/chap17.html)
 
-- [Cyclotomic numbers](https://www.gap-system.org/Manuals/doc/ref/chap18.html)
+- [Cyclotomic numbers](https://docs.gap-system.org/doc/ref/chap18.html)
 
-- [Floats](https://www.gap-system.org/Manuals/doc/ref/chap19.html)
+- [Floats](https://docs.gap-system.org/doc/ref/chap19.html)
 
-- [Finite Field Elements](https://www.gap-system.org/Manuals/doc/ref/chap59.html)
+- [Finite Field Elements](https://docs.gap-system.org/doc/ref/chap59.html)
 
-- [Permutations](https://www.gap-system.org/Manuals/doc/ref/chap42.html)
+- [Permutations](https://docs.gap-system.org/doc/ref/chap42.html)
 
-- [Lists](https://www.gap-system.org/Manuals/doc/ref/chap21.html)
+- [Lists](https://docs.gap-system.org/doc/ref/chap21.html)
 
-- [Records](https://www.gap-system.org/Manuals/doc/ref/chap29.html)
+- [Records](https://docs.gap-system.org/doc/ref/chap29.html)
 
-- [Strings and Characters](https://www.gap-system.org/Manuals/doc/ref/chap27.html)
+- [Strings and Characters](https://docs.gap-system.org/doc/ref/chap27.html)
 
 ## [Functions in GAP]({% link \_episodes/03-func.md %})
 
-- [GAP Tutorial: Functions](https://www.gap-system.org/Manuals/doc/tut/chap4.html)
+- [GAP Tutorial: Functions](https://docs.gap-system.org/doc/tut/chap4.html)
 
 ## [Using regression tests]({% link \_episodes/04-testing.md %})
 
-- [GAP Reference Manual: Test](https://www.gap-system.org/Manuals/doc/ref/chap7.html#X87712F9D8732193C)
+- [GAP Reference Manual: Test](https://docs.gap-system.org/doc/ref/chap7.html#X87712F9D8732193C)
 
 ## [Small groups search]({% link \_episodes/05-small-groups.md %})
 
-- [GAP Reference Manual: Group Libraries](https://www.gap-system.org/Manuals/doc/ref/chap50.html)
+- [GAP Reference Manual: Group Libraries](https://docs.gap-system.org/doc/ref/chap50.html)
 
 ## [Attributes and Methods]({% link \_episodes/06-attributes.md %})
 
-- [GAP Tutorial: Operations and Methods](https://www.gap-system.org/Manuals/doc/tut/chap8.html)
+- [GAP Tutorial: Operations and Methods](https://docs.gap-system.org/doc/tut/chap8.html)
 
-- [GAP Reference Manual: Adding a new Attribute](https://www.gap-system.org/Manuals/doc/ref/chap80.html#X874AF11D864AEC1B)
+- [GAP Reference Manual: Adding a new Attribute](https://docs.gap-system.org/doc/ref/chap80.html#X874AF11D864AEC1B)
 
 ## Glossary