feat: add canonical readlink

README.md

@@ -131,6 +131,22 @@ my_fun () {
 
 ```
 
+## `canonical_readlink $filepath`
+
+When you want to find out the directory the script you are currently running in, there are a number of UNIX filesystem indirections that are somewhat tricky to untangle. This function does that for you.
+
+Signature:
+
+```shell
+canonical_readlink filepath<string>
+```
+
+Usage:
+
+```shell
+my_dir=`canonical_readlink "$0"`
+```
+
 ## Debugging
 
 Set `DEBUG=1` to get debugging output.

canonical_readlink.sh

@@ -0,0 +1,12 @@
+# Copyright (c) 2022 Jan Lehnardt <jan@apache.org>, MIT licensed
+# via https://github.com/apache/couchdb/blob/1b8d4b73bc9ea67bfe0df5a41e24ea864f4c846d/rel/files/couchdb.in#L15 Apache 2 Licensed
+
+canonical_readlink () {
+	file=$(dirname "$1")/$(basename "$1");
+	if [ -h "file" ]; then
+		cd $(dirname "$1")
+		canonical_readlink $(readlink "file");
+	else
+		cd "${1%/*}" && pwd -P;
+	fi
+}

test/test.sh

@@ -26,4 +26,9 @@
 # 
 # echo test5
 # (wait_for_pid_exit 45591 4 17)
-# echo "test5 done"
+# echo "test5 done"
+
+# . canonical_readlink.sh
+#
+# my_path=`canonical_readlink "$0"`
+# echo $my_path