patch 8.0.1832: cannot use :unlet for an environment variable commit https://github.com/vim/vim/commit/137374fd6538cf9dee0cb22907728d8fdecb5832 Author: Bram Moolenaar <Bram@vim.org> Date: Sun May 13 15:59:50 2018 +0200 patch 8.0.1832: cannot use :unlet for an environment variable Problem: Cannot use :unlet for an environment variable. Solution: Make it work. Use unsetenv() if available. (Ken Takata, closes #2855)

--- a/src/eval.c
+++ b/src/eval.c
@@ -2758,6 +2758,20 @@ ex_unletlock(
 
     do
     {
+	if (*arg == '$')
+	{
+	    char_u    *name = ++arg;
+
+	    if (get_env_len(&arg) == 0)
+	    {
+		EMSG2(_(e_invarg2), name - 1);
+		return;
+	    }
+	    vim_unsetenv(name);
+	    arg = skipwhite(arg);
+	    continue;
+	}
+
 	/* Parse the name and find the end. */
 	name_end = get_lval(arg, NULL, &lv, TRUE, eap->skip || error, 0,
 							     FNE_CHECK_START);