Count the number of blank lines at the end of file

If your grep is the GNU grep, here is a quick and dirty solution:

grep -A1 "Prepare to remove role" | grep "Delete Successful" | wc -l

The grep option -A1 tells grep to print the matching line AND one line following the matching line. The second grep then only prints the lines where the delete is successfull.

Note that this will only work reliably when the "Prepare to remove role X" line is always immediately followed by the "Delete Successful" line.

Also note: you don't need wc -l because grep has that functionality built in:

grep -A1 "Prepare to remove role" | grep -c "Delete Successful"

{ grep -m1 match; grep -c ''; } <file

That will work w/ GNU grep and an lseek()able infile. The first grep will stop at 1 -match, and the second will -count every line remaining in input.

Without GNU grep:

{ sed '/match/q'; grep -c ''; } <file

Of course, w/ grep you can use any/all of its other options besides, and stopping at one match is not at all necessary.