Initial version of the script

Code copied from https://github.com/marcwrobel/jbanking/blob/2030a902dcd8c396a29520482cf2cbe94d2428a6/bin/check-links.

README.md

@@ -1,2 +1,7 @@
 # checklinks
-Helps check and fix links in a codebase.
+
+A project codebase often contains a lot of external links. checklinks is an utility that helps checking and fixing those links.
+
+```shell
+path/to/checklinks <directory-to-check>
+```

checklinks

@@ -0,0 +1,29 @@
+#!/usr/bin/env bash
+
+USER_AGENT='Mozilla/5.0 (X11; Linux x86_64; rv:91.0) Gecko/20100101 Firefox/91.0'
+RETRY=1
+RETRY_DELAY=10
+TIMEOUT=3 # seconds
+
+RED='\033[0;31m'
+GREEN='\033[0;32m'
+BLUE='\033[0;34m'
+NC='\033[0m' # No Color
+
+[ ! -d "$1" ] && echo "'$1'  is not a directory" && exit 1
+
+# Links are processed in a random order to reduce the risk of being blacklisted and temporarily blocked
+for url in $(grep -RioEh 'https?://[^][{} "`<>),*$|\\]*[^][{} "`<>),*$|\\.:'"'"']' | grep -vE 'https?://(localhost|[0-9]+|.+:[0-9]+|example|host|somehost|nohost|link|acme.org|foo.com|application.com|[^/]+.example.com|registry.npmjs.org|apache.org/xml/features|java.sun.com/xml/ns|javax.xml.XMLConstants)' | sort | uniq | sort -R); do
+  # we could use --head, but it is not always supported...
+  status=$(curl -o /dev/null --silent --connect-timeout "$TIMEOUT" --retry $RETRY --retry-delay $RETRY_DELAY --user-agent "$USER_AGENT" --location --write-out '%{http_code}' "$url")
+
+  if [ "$status" = "200" ]; then
+    if [[ $url =~ "http://" ]]; then
+      echo -e "${BLUE}$url ($status)${NC}"
+    else
+      echo -e "${GREEN}$url ($status)${NC}"
+    fi
+  else
+    echo -e "${RED}$url ($status)${NC}"
+  fi
+done