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nix3-build:tldr:cd83c
The command "nix build -L ${-#pkg}" is a command-line instruction that executes a build action using the Nix package manager. Let's break it down:
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"nix build": This is the command to initiate a build action with Nix. It is used to build Nix packages or derivations defined in Nix expressions.
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"-L": This is a flag or option for the "nix build" command. In this case, the "-L" flag is used to enable lazy evaluation of dependencies. Lazy evaluation means that only necessary components will be built, not the entire dependency tree.
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"${-#pkg}": This is a shell variable expansion or substitution syntax.
- The "$" signifies the start of a variable expansion.
- The "{-#pkg}" represents the variable name, "-#pkg".
- The "#"" is a parameter expansion operator used to remove the shortest match of "pkg" from the start of the variable. In other words, it removes the "pkg" prefix if there is any.
So, when this command is executed, the value of the shell variable "-#pkg" will be substituted, and the resulting command will be something like "nix build -L