vim comment multiple lines code example

Example 1: how to edit multiple lines in vim

Move the cursor to the appropriate location.
Enter 'VISUAL BLOCK' mode (Ctrl v).
Use your directional keys to select required number of lines (j or k).
Press I (capital i).
Press Esc.

Note: Once exited out of 'VISUAL BLOCK' mode, changes will take effect.

Example 2: vim replace multiple lines

# Replace all instances of foo with bar
:%s/foo/bar/g

# Replace all instances of foo in lines 6 to 10 inclusive with bar
:6,10s/foo/bar/g

Example 3: vim comment block

#for commenting:
Press ESC
:[StartNumber],[ENDNumber]s/^/#
:66,70s/^/#

for uncommenting:
Press ESC
:[StartNumber],[ENDNumber]s/^#/
:66,70s/^#/

#PS: To see line numbers:
Pres ESC
:set number