From 67250693997128ed8253aee3eec6e50a303ee5fa Mon Sep 17 00:00:00 2001
From: Rostislav Svoboda <Rostislav.Svoboda@gmail.com>
Date: Fri, 16 Feb 2024 15:05:20 +0100
Subject: [PATCH] notes

---
 notes/cli/linux.scrbl     | 13 ++++++++++++-
 notes/editors/emacs.scrbl |  3 +++
 2 files changed, 15 insertions(+), 1 deletion(-)

diff --git a/notes/cli/linux.scrbl b/notes/cli/linux.scrbl
index 5666657..a333b06 100644
--- a/notes/cli/linux.scrbl
+++ b/notes/cli/linux.scrbl
@@ -1036,9 +1036,20 @@
   # :xml command line XML tool (formating)
   xmllint
 
-  # shared library dependencies
+  # shared library / shared object dependencies
   ldd --verbose $(which vim)
 
+  # calculate the size of a shared library / shared object with its dependencies
+  # TODO The calculation doesn't work recursively. A shared object can require
+  # other shared objects. See https://news.ycombinator.com/item?id=39232976#39250540
+  guile=$(readlink -f $(which guile))
+  sizes=$({ echo $guile; ldd $guile|grep /|sed 's+^[^/]*\(/[^ ]*\).*+\1+'; }|xargs -n 1 readlink -f|xargs du -ab|cut -f 1)
+  sumsize=0
+  for size in $sizes; do
+      sumsize=$((sumsize+size));
+  done
+  echo $sumsize
+
   # :library find out if libgconf is installed
   # -p, --print-cache          Print cache
   ldconfig --print-cache | grep libgconf
diff --git a/notes/editors/emacs.scrbl b/notes/editors/emacs.scrbl
index 4944e2f..45693d2 100644
--- a/notes/editors/emacs.scrbl
+++ b/notes/editors/emacs.scrbl
@@ -91,6 +91,9 @@
 }
 
 @block{@block-name{Various}
+  ;; default value of an an optional parameter is nil
+  ((lambda (a &optional b) (list a b)) 'a) ; => (a nil)
+
   ;; check if FILENAME directory exists / is an existing directory
   (file-directory-p FILENAME)