2025 8 15 https://shelter.sirref.org/shelterfile-syntax/ shelterfile-syntax /shelterfile-syntax/ Shelterfile Syntax Shelterfiles, files with a .shl extension, are a funny mix of syntax borrowing from Dockerfiles and shell scripts. 2025 8 15 https://shelter.sirref.org/basix-syntax/ basix-syntax /basix-syntax/ Basic Syntax meta-commands Take the following Dockerfile for example: hello2.txt]]> In Shelter, this can be expressed very similarly. hello2.txt]]> We have had to use two meta-commands to achieve the same functionality. The first line creates a fresh session using the alpine base image. We then import a file from the local filesystem into our image. 2025 8 15 https://shelter.sirref.org/conditionals/ conditionals /conditionals/ Conditionals Unlike Dockerfiles, we have the possibility to introduce conditionals. Conditionals allow you to check a certain command exits with 0 and if so execute the first branch, otherwise execute the second branch. 2025 8 15 Syntax The synax is similar to many programming languages' implementation of if-then-else constructs. 2025 8 15 https://shelter.sirref.org/parallel-for/ parallel-for /parallel-for/ Parallel Loops Given Shelter's underlying mergeable structure, it can offer a rather unique model for parallel computation. Tools exist within the shell scripting world for taking scripts and arguments and running them in parallel. For example, GNU parallel or littlejohn. These tools, like Shelter, use processes for parallelism. Shelter, however, runs the processes in isolation using namespaces which gives us two advantages: It ensures that the parallel parts cannot interfere with one another. Each instantiation of the body of the loop starts from the same starting point Since each loop-body is independent, successful executions are recorded and do not need to be re-run in the event of a partial failure. After all parts of the loop have completed, the resulting data is merged and execution continues from there. By providing this as an extra feature, if users do not like these semantics, they can always opt to use a more generic tool for their parallelism too! 2025 8 15 Syntax For now, parallel for-loops are rather simplistic. #file }]]> You may introduce a variable, here file, which will take on the value in your referenced using # and will be replaced accordingly. References Context Backlinks The Shelter Developers 2025 7 21 https://shelter.sirref.org/index/ index /index/ Shelter Welcome to Shelter's documentation. Shelter is a metashell. A tool for managing shell sessions in a more reproducible way. To get started with Shelter, you can read the getting started tutorial. For a more thorough understanding of what Shelter offers and how to use it, then please follow the documentation. 2025 7 21 https://shelter.sirref.org/shelter-0001/ shelter-0001 /shelter-0001/ About Shelter's Documentation Shelter's documentation is written in using Forester via Graft. The main ethos is to divide the documentation into fairly small, standalone chunks. These can then be pieced together into documentation pages that are tightly linked. For reference documentation, we have: The Shelterfile syntax -- the syntax for shelterfiles, a mishmash of Dockerfiles and shell scripts. These are useful for setting up branches for developement The available meta-commands -- these extend past shell scripts and allow users to access the more interesting parts of Shelter like @ undo or @ merge <branch> for example. The development logs -- a set of developer logs about the activity on shelter. Related Contributions