Add Linux command to get full file path

src/linux.md

@@ -127,6 +127,9 @@ less file.txt
 
 # List all files in a directory, with full paths, into a text file.
 find wwwroot -type f > files.txt
+
+# Get full path to a file.
+readlink -f relative/path/to/file
 ```
 
 ### Hidden content
@@ -232,7 +235,7 @@ chmod o-rwx file-or-directory
 # Users, groups, and others have read, write, and execute.
 chmod ugo+rwx file-or-directory
 
-# Only read to all.
+# Grant all users read-only access to a file or directory.
 chmod a=r file-or-directory
 
 # View permissions.