Update bash-extracting_from_files.md

docs/pages/bash/bash-extracting_from_files.md

 # Extracting from files
 
-## Extracting begining/end (head, tail)
+## Displaying sample (head, tail)
 
 ## Counting lines (wc)
 
 ## Sorting a tabular file (sort)
 
-## Searching pattern (grep)
+## Searching patterns (grep)
 
-## Redirecting a command output (>)
+## Redirecting an output (>)
 
 ## Combining commands (|)
 
-## Replacing pattern (sed)
+## Replacing patterns (sed)
 
 ## Extracting columns (cut)