diff --git a/check_licenses.sh b/check_licenses.sh
index c02b162..aad8cd3 100755
--- a/check_licenses.sh
+++ b/check_licenses.sh
@@ -1,4 +1,38 @@
 #!/bin/sh
-# Depends on: `rg` (ripgrep)
 
-! rg --multiline --files-without-match --glob '*.rs' --pcre2  '(?<!\n)((//)|(#)) Copyright \(c\) \d+ [A-z, ]+\n((//)|(#)) SPDX-License-Identifier: .*\n'
+set -e
+
+# check if we have tomcat(1)
+if ! command -v tomcat >/dev/null 2>&1; then
+	printf "%s: Missing dependency: tomcat(1)\n"
+	exit 69 # sysexits(3) EX_UNAVAILABLE
+fi
+
+dir="$(pwd | sed 's/\//\n/g' | tail -n 1)"
+
+for toml in $(find "$PWD" -name "Cargo.toml"); do
+	printf "Project: %s\n" "$(tomcat package.name "$toml")"
+	for file in $(find "$(printf "%s\n" "$toml" |\
+		sed 's/Cargo\.toml/src/g')" -name "*.rs")
+	do
+		info="$(head -n 2 "$file")"
+		toml_lic="$(tomcat package.license "$toml")"
+		if ! test -n "$toml_lic"; then
+			printf "%s: Missing license information\n" "$(printf "%s\n" "$toml" |\
+				sed "s/^.\+$dir\///g")"
+			continue 2
+		fi
+		if ! [ "$toml_lic" = "$(printf "%s\n" "$info" | tail -n 1 |\
+			sed -n 's/\/\/ SPDX-License-Identifier: //p')" ]
+		then
+			printf "%s: Missing or malformed license information\n" \
+				"$(printf "%s\n" "$file" | sed "s/^.\+$dir\///g")"
+		fi
+		if ! test -n "$(printf "%s\n" "$info" | head -n 1 |\
+			sed -n '/\/\/ Copyright (c) .\+/p')"
+		then
+			printf "%s: Missing or malformed copyright holder information\n" \
+        "$(printf "%s\n" "$file" | sed "s/^.\+$dir\///g")"
+		fi
+	done
+done