ZiomekOS v26.9.26

meta/render.sh

@@ -0,0 +1,47 @@
+#!/usr/bin/env /bin/bash
+# Co-Authored by: Claude (Sonnet 5.5 Medium)
+# Usage: render.sh src/path/file.in [../vars.sh]
+set -euo pipefail
+
+in=$1
+vars_file=${2:-../vars.sh}
+
+case $in in
+    src/*) ;;
+    *) echo "render.sh: input must be under src/: $in" >&2; exit 1 ;;
+esac
+
+# src/etc/issue.in -> build/etc/issue
+out=build/${in#src/}
+out=${out%.in}
+
+# Load variables from vars.sh and export them for envsubst
+if [[ -n $vars_file ]]; then
+    set -a
+    # shellcheck disable=SC1090
+    source "$vars_file"
+    set +a
+fi
+
+# Only substitute ${VAR} references that actually appear in the template,
+# so anything else (like \n or \l) is left untouched
+refs=$(grep -oE '\$\{[A-Za-z_][A-Za-z0-9_]*\}' "$in" | sort -u || true)
+
+# Fail loudly on undefined variables instead of silently emitting empty strings
+for ref in $refs; do
+    name=${ref#\$\{}; name=${name%\}}
+    if [[ -z ${!name+x} ]]; then
+        echo "render.sh: $in uses undefined variable $name" >&2
+        exit 1
+    fi
+done
+
+mkdir -p "$(dirname "$out")"
+
+# Write to a temp file first so a failure never leaves a half-written output
+tmp=$(mktemp "$out.XXXXXX")
+trap 'rm -f "$tmp"' EXIT
+envsubst "$(echo $refs)" < "$in" > "$tmp"
+chmod 644 "$tmp"
+mv "$tmp" "$out"
+trap - EXIT