lsof: shorten main desc, expand PID acronym (#1346)

pages/common/lsof.md

@@ -1,7 +1,7 @@
 # lsof
 
 > Lists open files and the corresponding processes.
-> Note: In most cases, you need root privilege (or use sudo) because you want to list files opened by others.
+> Note: Root privileges (or sudo) is required to list files opened by others.
 
 - Find the processes that have a given file open:
 
@@ -11,7 +11,7 @@
 
 `lsof -i :{{port}}`
 
-- Only output the process PID:
+- Only output the process ID (PID):
 
 `lsof -t {{/path/to/file}}`
 
@@ -23,6 +23,6 @@
 
 `lsof -c {{process_or_command_name}}`
 
-- List files opened by the given PID:
+- List files opened by a specific process, given its PID:
 
 `lsof -p {{PID}}`