Import PoC

realpath.sh

@@ -0,0 +1,10 @@
+#!/bin/sh
+p="$1"
+target=$(readlink "$p")
+
+case "$target" in
+/*) p="$target";;
+*) p="${p%/*}/$target";;
+esac
+
+printf "%s\n" "$p"|sed -e 's@/[^/]*/\.\.\(/\|$\)@/@g' -e 's|/\.\(/\|$\)|/|g' -e 's|/$||g'

test.sh

@@ -0,0 +1,35 @@
+#!/bin/sh
+bin=$PWD/realpath.sh
+dir="$(mktemp -d)"
+cd "$dir"
+
+do_test() {
+  name=$dir/$2
+  target=$3
+  case "$name" in
+  */*) mkdir -p "${name%/*}";;
+  esac
+
+  ln -s "$target" "$name"
+
+  is=$($bin "$name")
+
+  should=$(readlink -f "$name")
+
+  if [ "$is" == "$should" ]; then
+    echo "Test $1 success"
+  else
+    echo "Test $1 fail: \"${bin##*/} $name\" returned \"$is\" instead of \"$should\""
+    stat "$name"
+  fi
+  rm -r "$name"
+}
+
+touch t
+
+do_test 1 a /bin
+do_test 2 a/b .
+do_test 3 a/b ..
+do_test 4 a/b ../t
+
+rm -rf "$dir"