diff --git a/docs/libraries.md b/docs/libraries.md
index cbefa4e..635e475 100644
--- a/docs/libraries.md
+++ b/docs/libraries.md
@@ -380,9 +380,45 @@ And for a tutorial, see <https://lispcookbook.github.io/cl-cookbook/databases.ht
 
 ## Files and directories
 
-CL has built-in functions to deal with files and directories and UIOP provides more. See [https://lispcookbook.github.io/cl-cookbook/files.html](https://lispcookbook.github.io/cl-cookbook/files.html).
+CL has built-in functions to deal with files and directories, and UIOP provides more. See [https://lispcookbook.github.io/cl-cookbook/files.html](https://lispcookbook.github.io/cl-cookbook/files.html).
 
-See also some functions under `uiop/os` (or simply `uiop` or `os` for short) like `os:getcwd`.
+See some functions under `uiop`, especially under `uiop/filesystem` (`filesystem` for short) like `filesystem:file-exists-p`, and some more under `uiop/os` (or just `os`) like `os:getcwd`.
+
+Example functions (not exhaustive):
+
+```
+filesystem:call-with-current-directory
+filesystem:collect-sub*directories
+filesystem:delete-directory-tree
+filesystem:delete-empty-directory
+filesystem:delete-file-if-exists
+filesystem:directory*
+filesystem:directory-exists-p
+filesystem:directory-files
+filesystem:ensure-all-directories-exist
+filesystem:file-exists-p
+filesystem:filter-logical-directory-results
+filesystem:get-pathname-defaults
+filesystem:getenv-absolute-directories
+filesystem:getenv-absolute-directory
+filesystem:getenv-pathname
+filesystem:getenv-pathnames
+filesystem:inter-directory-separator
+filesystem:lisp-implementation-directory
+filesystem:lisp-implementation-pathname-p
+filesystem:native-namestring
+filesystem:parse-native-namestring
+filesystem:probe-file*
+filesystem:rename-file-overwriting-target
+filesystem:resolve-symlinks
+filesystem:resolve-symlinks*
+filesystem:safe-file-write-date
+filesystem:split-native-pathnames-string
+filesystem:subdirectories
+filesystem:truename*
+filesystem:truenamize
+filesystem:with-current-directory
+```
 
 We include the [FOF (File-object finder)](https://gitlab.com/ambrevar/fof/) library, which is very useful to:
 
@@ -398,7 +434,6 @@ In practice, it mostly supersedes:
 - Common Lisp pathnames (at least for existing files).
 - Many Unix tools:
   - `find` for recursive and programmable file search. Unlike `find`, `finder`'s predicates are extensible.
-  - `ls`
   - `stat`
   - `chown`
   - `chmod`
diff --git a/docs/scripting.md b/docs/scripting.md
index 1741d0f..1060a4c 100644
--- a/docs/scripting.md
+++ b/docs/scripting.md
@@ -30,7 +30,7 @@ An example script:
 (cmd:cmd "ls")
 
 ;; Access environment variables:
-(hello (uiop:getenv "USER"))
+(hello (os:getenv "USER"))  ;; os is a nickname for uiop/os
 
 (format! t "Let's define an alias to run shell commands with '!'. This gives: ")
 (defalias ! #'cmd:cmd)
diff --git a/src/packages.lisp b/src/packages.lisp
index 971e6c3..408b7b1 100644
--- a/src/packages.lisp
+++ b/src/packages.lisp
@@ -3,19 +3,20 @@
 (uiop:define-package ciel
   (:use :cl)
   (:export #:enable-shell-passthrough
-           #:-->)
-  (:local-nicknames (:/os :uiop/os)
-                    ;; let's try this nickname.
-                    ;; Simply :os doesn't help at auto-discovery with SLIME's autocompletion.
-                    ;; but let's add it anyways for correctness.
-                    (:os :uiop/os)
-                    (:alex :alexandria)
-                    (:csv :cl-csv)
-                    (:http :dexador)))
+           #:-->))
 
 (uiop:define-package ciel-user
   (:use :cl :ciel)
-  (:local-nicknames (:csv :cl-csv)
+  (:local-nicknames (:/os :uiop/os)     ; let's try this nickname.
+                    ;; Simply :os doesn't help at auto-discovery with SLIME's autocompletion.
+                    ;; But let's add it anyways for correctness,
+                    ;; it's handy for the shell and scripts.
+                    (:os :uiop/os)
+                    ;; This other uiop module is always useful:
+                    (:filesystem :uiop/filesystem)
+
+                    (:alex :alexandria)
+                    (:csv :cl-csv)
                     (:http :dexador)
                     (:json :shasht)))