commit 3400f9f90fce3270b48d05f3f54d140331e23828
Author: E. S. <the@rootless.one>
Date:   Sun Dec 31 23:40:28 2023 +0300

    initial

diff --git a/.gitignore b/.gitignore
new file mode 100644
index 0000000..757fee3
--- /dev/null
+++ b/.gitignore
@@ -0,0 +1 @@
+/.idea
\ No newline at end of file
diff --git a/release-book.sh b/release-book.sh
new file mode 100755
index 0000000..59081e2
--- /dev/null
+++ b/release-book.sh
@@ -0,0 +1,47 @@
+#!/bin/sh
+
+FILES_DIR="$HOME/files"
+ARCHIVE_DIR="$FILES_DIR/4in1-old-versions"
+
+fatal() {
+	>&2 echo "error: $@"
+	exit 1
+}
+
+get_modification_time() {
+    file_path="$1"
+
+    if [ ! -e "$file_path" ]; then
+    	fatal "file not found: $file_path"
+    fi
+
+    mod_time=$(stat -c "%Y" "$file_path")
+    formatted_mod_time=$(date -d "@$mod_time" "+%Y-%m-%d")
+    echo "$formatted_mod_time"
+}
+
+usage() {
+	>&2 echo "usage: $0 <filename> en|ru"
+}
+
+[ $# -ne 2 ] && { usage; exit 1; }
+
+INPUT="$1"
+LANG="$2"
+
+case $LANG in
+    en|ru) : ;;
+    *) fatal "invalid language" ;;
+esac
+
+target_file="$FILES_DIR/4in1-$LANG.pdf"
+old_date="$(get_modification_time "$INPUT")"
+
+[ -d "$ARCHIVE_DIR" ] || {
+	mkdir "$ARCHIVE_DIR"
+	chmod 755 "$ARCHIVE_DIR"
+	chgrp www-data "$ARCHIVE_DIR"
+}
+
+mv "$target_file" "$ARCHIVE_DIR/4in1-$LANG-$old_date.pdf"
+mv "$INPUT" "$target_file"
\ No newline at end of file