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R""(
# Examples
* Display all special commands within the REPL:
```console
# nix repl
nix-repl> :?
```
* Evaluate some simple Nix expressions:
```console
# nix repl
nix-repl> 1 + 2
3
nix-repl> map (x: x * 2) [1 2 3]
[ 2 4 6 ]
```
* Interact with Nixpkgs in the REPL:
```console
# nix repl --file example.nix
Loading Installable ''...
Added 3 variables.
# nix repl --expr '{a={b=3;c=4;};}'
Loading Installable ''...
Added 1 variables.
# nix repl --expr '{a={b=3;c=4;};}' a
Loading Installable ''...
Added 1 variables.
# nix repl --extra_experimental_features 'flakes repl-flake' nixpkgs
Loading Installable 'flake:nixpkgs#'...
Added 5 variables.
nix-repl> legacyPackages.x86_64-linux.emacs.name
"emacs-27.1"
nix-repl> legacyPackages.x86_64-linux.emacs.name
"emacs-27.1"
nix-repl> :q
# nix repl --expr 'import <nixpkgs>{}'
Loading Installable ''...
Added 12439 variables.
nix-repl> emacs.name
"emacs-27.1"
nix-repl> emacs.drvPath
"/nix/store/lp0sjrhgg03y2n0l10n70rg0k7hhyz0l-emacs-27.1.drv"
nix-repl> drv = runCommand "hello" { buildInputs = [ hello ]; } "hello; hello > $out"
nix-repl> :b drv
this derivation produced the following outputs:
out -> /nix/store/0njwbgwmkwls0w5dv9mpc1pq5fj39q0l-hello
nix-repl> builtins.readFile drv
"Hello, world!\n"
nix-repl> :log drv
Hello, world!
```
# Description
This command provides an interactive environment for evaluating Nix
expressions. (REPL stands for 'read–eval–print loop'.)
On startup, it loads the Nix expressions named *files* and adds them
into the lexical scope. You can load addition files using the `:l
<filename>` command, or reload all files using `:r`.
)""
|
