ghc:tldr:0ac5e

The command ghc -O ${file-hs} is used to compile a Haskell source code file (with the file extension .hs) using the Glasgow Haskell Compiler (GHC) with the optimization flag (-O).

Let's break down the command:

• ghc: This is the command to invoke the Glasgow Haskell Compiler. It is responsible for compiling Haskell code into executable binaries.

• -O: This is an optimization flag that instructs the GHC to perform various optimizations during compilation, such as inlining function calls and optimizing code size and efficiency. This can result in faster and more efficient executables.

• ${file-hs}: This is a placeholder for the actual file name, represented as ${file-hs}. You would need to replace this placeholder with the name of your specific Haskell source code file (with the .hs file extension). For example, if your file is named example.hs, the command would become ghc -O example.hs.

When you run this command, GHC takes your Haskell source code file, compiles it, and produces an executable binary file (with the default name a.out if you didn't specify an output file name). This binary can then be executed to run your Haskell program. The optimization flag (-O) helps improve the performance and efficiency of the generated binary.