Fixed typos, titles and spacing

knowledge base/atom.md

@@ -7,7 +7,7 @@
 Change font to `NotoSansMono Nerd Font` in Platformio Ide Terminal's settings.  
 See [Why Zsh terminal icons are not getting displayed in Atom Platformio Ide Terminal?]
 
-## Sources
+## Further readings
 
 - [Why Zsh terminal icons are not getting displayed in Atom Platformio Ide Terminal?]
 

knowledge base/grep the standard error stream.md

@@ -26,13 +26,10 @@ command 1>/dev/null 2> >(grep -oP "(.*)(?=pattern)")
 > Do note that **the target command of process substitution runs asynchronously**.  
 > As a consequence, `stderr` lines that get through the grep filter may not appear at the place you would expect in the rest of the output, but even on your next command prompt.
 
-## See also
-
-- Knowledge base on [grep]
-
 ## Further readings
 
 - Answer on [StackExchange] about [how to grep the standard error stream]
+- Knowledge base on [grep]
 
 [grep]: grep.md
 

knowledge base/mount samba shares from a unix client.md

@@ -6,7 +6,7 @@
 sudo mount -t cifs -o user=my-user //nas.local/shared_folder local_folder
 ```
 
-## Sources
+## Further readings
 
 - [Mounting samba shares from a unix client]
 

knowledge base/opkg.md

@@ -38,7 +38,7 @@ opkg list-changed-conffiles
 opkg depends dropbear
 ```
 
-## Sources
+## Further readings
 
 - [Opkg package manager]
 

knowledge base/pre-commit.md

@@ -22,12 +22,8 @@ SKIP=flake8 git commit -m "foo"
 
 ## Further readings
 
+- Pre-commit's [website]
 - List of [supported hooks]
 
 [supported hooks]: https://pre-commit.com/hooks.html
-
-## Sources
-
-- [Website]
-
 [website]: https://pre-commit.com

knowledge base/rotate a pdf file.md

@@ -0,0 +1,7 @@
+# Rotate a PDF file
+
+## Further readings
+
+- [pdftk]
+
+[pdftk]: pdftk.md#rotate-a-file

knowledge base/sponge.md

@@ -9,7 +9,7 @@ brew install sponge   # or moreutils
 # append file content to the source file
 cat path/to/file | sponge -a path/to/other/file
 
-# remove all lines starting with # in a file:
+# remove all lines starting with "#" in a file
 grep -v '^{{#}}' path/to/file | sponge path/to/other/file
 ```