Writing bash scripts with Nix

source/_notes/3.md

@@ -0,0 +1,48 @@
+---
+title: Writing bash scripts with Nix
+date: 2024-08-21 18:30:24
+tags: [Bash, Linux, Nix]
+---
+
+- Variables, such as username, can be injected.
+- `shellcheck` is run automatically with `pkgs.writeShellApplication`.
+- Packages defined in `runtimeInputs` will be automatically injected.
+
+<https://github.com/opdavies/dotfiles.nix/blob/a1c356a1f576f041301a5c41d6ba7d0f098d0edb/lib/shared/scripts/export-video-list.nix>
+
+```nix
+{ pkgs, username, ... }:
+
+{
+  name = "export-video-list";
+
+  runtimeInputs = with pkgs; [
+    jq
+    tree
+    udisks
+  ];
+
+  text = ''
+    device_name="/dev/sda2"
+    device_label="UNTITLED"
+
+    source_path="/run/media/${username}/$device_label"
+
+    # If the source path doesn't exist, try mounting the device.
+    if [[ ! -d "$source_path" ]]; then
+      ${pkgs.udisks}/bin/udisksctl mount -b "$device_name"
+    fi
+
+    # Exit early if the source path still doesn't exist.
+    if [[ ! -d "$source_path" ]]; then
+      echo "Error: $source_path not found."
+      exit 1
+    fi
+
+    output_file="$HOME/Documents/videos.json"
+
+    ${pkgs.tree}/bin/tree -J "$source_path/Videos" | ${pkgs.jq}/bin/jq . > "$output_file"
+    ${pkgs.jq}/bin/jq . < "$output_file"
+  '';
+}
+```