build: testing new build

scripts/prepare-markdown-for-ebook.sh

@@ -1,32 +1,33 @@
 #!/usr/bin/env bash
-# This script prepares a `hacker-laws.md` file for export to PDF or e-book format.
 
-# Require a version number and get the current date.
-version=$1
-date=$(date "+%Y-%m-%d")
+# Fail on errors.
+set -e -o pipefail
 
-if [ -z "$version" ]; then
-    echo "Usage: $0 <version>"
+# Check if parameters are provided
+input="$1"
+output="$2"
+if [ -z "${input}" ] || [ -z "${output}" ]; then
+    echo "usage: $(basename "$0") <input> <output>" >&2
+    echo "  input: source markdown file (usually README.md)" >&2
+    echo "  output: output markdown file (usually hacker-laws.md)" >&2
     exit 1
 fi
 
-# Create `hacker-laws.md` with frontmatter and README content in one step.
-cat << EOF > hacker-laws.md
----
-title: "Hacker Laws"
-author: "Dave Kerr, github.com/dwmkerr/hacker-laws"
-subtitle: "Laws, Theories, Principles, and Patterns that developers will find useful. ${version}, ${date}."
----
+# Grab env vars used to configure output, fail if required are missing.
+export date="${DATE:-$(date +%F)}"
+export version="${VERSION?error: VERSION must be set}"
 
-EOF
-cat README.md >> hacker-laws.md
+# Update the input file to an intermedate.
+intermediate="${input}.temp"
+DATE="${date}" VERSION="${version}" envsubst < "${input}" > "${intermediate}"
 
 # Use a single `sed` command to clean up unwanted lines and emojis in one pass.
-sed -i'' -e '/💻📖.*/d' \
+sed      -e '/💻📖.*/d' \
          -e 's/❗/Warning/g' \
          -e '/^\[Translations.*/d' \
          -e '/\*.*/d' \
          -e '/    \*.*/d' \
-         -e '/## Translations/,$d' hacker-laws.md
+         -e '/## Translations/,$d' "${intermediate}" > "${output}"
+rm "${intermediate}"
 
-echo "hacker-laws.md prepared successfully."
+echo "${output} prepared successfully."